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autoconf/NEWS
Paul Eggert 9c01837246 Tone down year-2038 changes 
New macro AC_SYS_YEAR2038_RECOMMENDED replaces new macro
AC_SYS_YEAR2038_REQUIRED, and gives the builder an out of
specifying --disable-year2038.  Remove new macro
AC_SYS_LARGEFILE_REQUIRED, which was added only for symmetry and
does not seem to have a great need.
* NEWS, doc/autoconf.texi: Document this.
* lib/autoconf/specific.m4:
Be more specific about mid-January 2038 than just Jan 2038.
(_AC_SYS_YEAR2038_PROBE): Ignore IF-NOT-DETECTED arg.
If support is not detected, merely set ac_have_year2038=no instead
of erroring out.  All callers changed.
(_AC_SYS_YEAR2038_OPT_IN): Remove.  All callers removed.
(AC_SYS_YEAR2038): Simplify by requiring AC_SYS_LARGEFILE
and then testing the result.
(AC_SYS_YEAR2038_REQUIRED, AC_SYS_LARGEFILE_REQUIRED): Remove.
(AC_SYS_YEAR2038_RECOMMENDED): New macro.
(_AC_SYS_LARGEFILE_PROBE): If support is not detected, merely set
ac_have_largefile=no instead of erroring out.  All callers changed.
Take on the burden of invoking year2038 probe as needed.
(AC_SYS_LARGEFILE): Simplify.
2023-04-26 18:37:10 -07:00

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GNU Autoconf NEWS - User visible changes.
* Noteworthy changes in release ?.? (????-??-??) [?]
** Backward incompatibilities
*** AC_CHECK_FUNC and similar macros now use function prototypes.
This should work better with C23, which removed the non-prototyped K&R
style that AC_CHECK_FUNC previously used. However, this change
means Autoconf no longer supports pre-1989 C compilers, as they do
not support function prototypes.
*** Autoconf developers now need Perl 5.10 (2007) or later.
Generated 'configure' scripts continue to run without Perl.
Although Autoconf users still need only Perl 5.6 (2000) or later,
Perl 5.10 or later is recommended for users too, as it avoids some
trouble with files that have timestamps separated by less than 1 s.
Due to limitations in Perl's API this trouble is not entirely fixed
even with Perl 5.36, which cannot represent timestamps separated by
238 ns or less, for circa 2023 timestamps on typical platforms.
*** Autoconf now requires GNU M4 1.4.8 (2006) or later.
Generated 'configure' scripts continue to run without M4.
Use of GNU M4 1.4.16 or later is recommended, as all earlier versions
are known to have had serious bugs in the text-processing builtins
on some, but not all, operating systems. Autoconf’s own configure
script will attempt to find a version of M4 that is not affected by
these bugs.
Note: Autoconf 2.70 and 2.71 include code that malfunctions with
M4 1.4.6 or 1.4.7. However, the only effect of the malfunction is
that you will get a confusing error message if you run autoconf on
a configure.ac that neglects to use AC_INIT or AC_OUTPUT.
*** m4sh diversions like BINSH have been renumbered.
This matters only for uses that, contrary to the documentation
and despite warnings, use m4_divert with numbered diversions.
*** AC_FUNC_GETGROUPS and AC_TYPE_GETGROUPS no longer run test programs.
These macros were testing for OS bugs that we believe are at least
twenty years in the past. Most operating systems are now trusted to
provide an accurate prototype for getgroups in unistd.h, and to
implement it as specified in POSIX.
AC_FUNC_GETGROUPS still includes a short blacklist of OSes with
known, severe bugs in getgroups. It can be overridden using
config.site. If you encounter a mistake in this blacklist
please report it to bug-autoconf.
** New features
*** New macros AC_SYS_YEAR2038 and AC_SYS_YEAR2038_RECOMMENDED.
This causes 'configure' to widen time_t if possible on systems where
time_t by default cannot represent file and other timestamps after
January 2038. Widening is possible only on 32-bit GNU/Linux x86 and
ARM systems with glibc 2.34 or later. To prevent widening,
configure with --disable-year2038.
This macro also has the effects as AC_SYS_LARGEFILE, because in
practice time_t cannot be widened without large-file sypport.
Application and library builders should take care that packages
configured with --enable-year2038 and --disable-year2038 options
are configured consistently, to avoid breaking binary compatibility.
This is similar to longstanding consistency requirements with
--enable-largefile and --disable-largefile.
AC_SYS_YEAR2038_RECOMMENDED acts like AC_SYS_YEAR2038 except that
'configure' fails if the target lacks support for post-2038
timestamps and --disable-year2038 is not given.
*** AC_SYS_LARGEFILE now optionally arranges to widen time_t.
It now acts like AC_SYS_YEAR2038, except 'configure' defaults to
--disable-year2038 unless either AC_SYS_YEAR2038 or
AC_SYS_YEAR2038_RECOMMENDED is also present.
*** AC_USE_SYSTEM_EXTENSIONS now enables C23 Annex F extensions
by defining __STDC_WANT_IEC_60559_EXT__.
** Obsolete features and new warnings
*** Autoconf now quotes 'like this' instead of `like this'.
Autoconf’s diagnostics now follow current GNU coding standards,
which say that diagnostics in the C locale should quote 'like this'
with plain apostrophes instead of the older GNU style `like this'
with grave accent and apostrophe.
*** AC_PROG_GCC_TRADITIONAL no longer does anything.
This macro has had no useful effect since GCC dropped support for
traditional-mode compilation in version 3.3 (released in 2003), and
the systems that needed it are also long obsolete. It is now a
compatibility synonym for AC_PROG_CC.
** Notable bug fixes
*** Autoconf caches now use finer-grained timestamps.
Autoconf now uses floating-point numbers rather than integers to
represent cache file timestamps, thus avoiding some problems where
automake incorrectly decides not to regenerate stale caches.
*** AC_HEADER_STDBOOL, AC_CHECK_HEADER_STDBOOL are obsolescent and less picky.
These macros are now obsolescent, as programs can simply include
stdbool.h unconditionally. If you use these macros, they now accept
a stdbool.h that exists but does nothing, so long as ‘bool’, ‘true’,
and ‘false’ work anyway. This is for compatibility with C23 and
with C++.
*** AC_PROG_MKDIR_P now falls back on plain 'mkdir -p'.
When AC_PROG_MKDIR_P cannot find a mkdir implementation that is
known to lack race condition bugs, it now falls back on 'mkdir -p'
instead of falling back on a relative path to install-sh, as the
relative paths now seem to be a more important problem than the
problems of ancient mkdir implementations with race condition bugs.
See <https://savannah.gnu.org/support/?110740>. The only ancient
mkdir still supported is Solaris 10 /usr/bin/mkdir, and for that
platform AC_PROG_MKDIR_P falls back on /opt/sfw/bin/mkdir which
should work if it is installed; if not, you should avoid parallel
'make' on that platform.
* Noteworthy changes in release 2.71 (2021-01-28) [stable]
** Bug fixes, including:
*** Compilers that support C99 but not C2011 are detected correctly.
*** Compatibility improved with clang and Oracle C++.
*** Compatibility restored with automake's rules for regenerating configure.
*** Compatibility restored with old versions of std-gnu11.m4.
Packages that wish to maintain compatibility with Autoconf 2.69 or
older, should update their copy of std-gnu11.m4 from Gnulib as soon
as practical, as the compatibility code bulks up the configure script.
Packages that require Autoconf 2.70 can drop this file entirely.
* Noteworthy changes in release 2.70 (2020-12-08) [stable]
** Backward incompatibilities:
*** Warnings about obsolete constructs are now on by default.
These warnings can be turned off with ‘-Wno-obsolete’.
Many of these warnings advise maintainers to run autoupdate.
Be aware that autoupdate cannot solve all backward compatibility
problems, and cannot completely solve all of the problems it does
address. A configure script edited by autoupdate is likely to
need further manual fix-ups.
*** Many macros have become pickier about argument quotation.
If you get a shell syntax error from your generated configure
script, or seemingly impossible misbehavior (e.g. entire blocks of
the configure script not getting executed), check first that all
macro arguments are properly quoted. The “M4 Quotation” section of
the manual explains how to quote macro arguments properly.
It is unfortunately not possible for autoupdate to correct
quotation errors.
*** Many macros no longer AC_REQUIRE as many other macros as they used to.
This can expose several classes of latent bugs. These are the ones
we know about:
- Make sure to explicitly invoke all of the macros that set result
variables used later in the configure script, or in generated
Makefiles.
- Autoconf macros that use AC_REQUIRE are not safe to use in shell
control-flow constructs that appear outside of macros defined by
AC_DEFUN. Use AS_IF, AS_CASE, etc. instead. (See the
“Prerequisite Macros” section of the manual for details.)
The set of macros that use AC_REQUIRE internally may change from
release to release. The only macros that are guaranteed *not* to
use AC_REQUIRE are the macros for acting on the results of a
test: AC_DEFINE, AC_SUBST, AC_MSG_*, AC_CACHE_CHECK, etc.
- AC_REQUIRE cannot be applied to macros that need to be used with
arguments. Instead, invoke the macro normally, with its arguments.
*** More macros use config.sub and config.guess internally.
As a consequence of improved support for cross compilation (see below),
more macros now use the auxiliary scripts ‘config.sub’ and ‘config.guess’.
If you use any of the affected macros, these scripts must be available
when your configure script is run, even if you have no intention of
ever cross-compiling your program.
autoreconf will issue an error if any auxiliary scripts are needed but
cannot be found. (It is not currently possible to make autoconf
itself issue this error.)
‘autoreconf --install’ will add ‘config.sub’, ‘config.guess’, and
‘install-sh’ to your source tree if they are needed. If you are
using Automake, scripts added to your tree by ‘autoreconf --install’
will automatically be included in the tarball produced by ‘make dist’;
otherwise, you will need to arrange for them to be distributed
yourself.
See the “Input” section of the manual for more detail, including
where to get the auxiliary scripts that may be needed by autoconf macros.
*** Setting CC to a C++ compiler is no longer supported.
The C and C++ languages have diverged enough that we can no longer
guarantee that test C programs will be processed as intended by a
C++ compiler. In this release, configure will proceed anyway, but
many test results will be incorrect. In a future release, we may
make AC_PROG_CC error out if it detects that CC is a C++ compiler.
See the “Language Choice” section of the manual for instructions on
how to write configure scripts for C++ programs, and for programs
with code in more than one language.
*** Running configure tests with warnings promoted to errors is not supported.
For instance, setting ‘CC="gcc -Werror"’ on the configure command
line, or adding -Werror to CFLAGS early in the configure script when
the compiler recognizes this option, is very likely to cause
subsequent tests to fail.
This has never been guaranteed to work; the code generated by
AC_CHECK_FUNC, for instance, is incorrect by a strict reading of the
original 1989 C standard, and has been ever since that macro was
introduced. Problems are more likely with newer, pickier compilers.
To enable compiler warnings and/or warnings-as-errors mode for your
own code, we currently recommend a dedicated Makefile variable
(e.g. ‘WARN_CFLAGS’) that is set by AC_SUBST when appropriate.
The Gnulib ‘warnings’ and ‘manywarnings’ modules can help with this.
We plan to add core support for probing for useful sets of compiler
warnings in a future release.
*** Including confdefs.h manually may cause test failures.
This has never been necessary; confdefs.h is automatically included
at the beginning of all test programs (by AC_LANG_SOURCE). Because
of the way confdefs.h is generated and used, it is not practical to
give it a multiple inclusion guard. Therefore, if you include it
yourself, all of its definitions will be scanned twice.
Historically this has not been a problem, because confdefs.h only
makes macro definitions, and the C standard allows redefinitions
of macros as long as they’re exactly the same, but newer, pickier
compilers may complain anyway (see for instance GCC bug 97998).
*** Older versions of automake and aclocal (< 1.8) are no longer supported.
*** AC_CONFIG_SUBDIRS no longer directly supports Cygnus configure.
If you are still using an Autoconf script to drive configuration of
a multi-package build tree where some subdirectories use Cygnus
configure, copy or link $ac_aux_dir/configure into each subdirectory
where it is needed. Please also contact us; we were under the
impression nobody used this very old tool anymore.
*** AC_CHECK_HEADER and AC_CHECK_HEADERS only do a compilation test.
This completes the transition from preprocessor-based header tests
begun in Autoconf 2.56.
The double test that was the default since Autoconf 2.64 is no
longer available. You can still request a preprocessor-only test
by specifying [-] as the fourth argument to either macro, but this
is now deprecated. If you really need that behavior use
AC_PREPROC_IFELSE.
*** AC_INCLUDES_DEFAULT assumes an ISO C90 compliant C implementation.
Specifically, it assumes that the ISO C90 header <stddef.h>
is available, without checking for it, and it does not include
the pre-standard header <memory.h> at all. If the POSIX header
<strings.h> exists, it will be included, without first testing
whether both <string.h> and <strings.h> can be included in the
same source file.
AC_INCLUDES_DEFAULT still checks for the existence of <stdlib.h>,
<string.h>, and <stdio.h>, because these headers may not exist
in a “freestanding environment” (a compilation mode intended for OS
kernels and similar, where most of the features of the C library are
optional). Most programs need not use ‘#ifdef HAVE_STDLIB_H’ etc in
their own code.
For compatibility’s sake, the C preprocessor macro STDC_HEADERS
will be defined when both <stdlib.h> and <string.h> are available;
however, <stdarg.h> and <float.h> are no longer checked for
(these, like <stddef.h>, are required to exist in a freestanding
environment). New code should not refer to this macro.
Future releases of Autoconf may reduce the set of headers checked
for by AC_INCLUDES_DEFAULT.
*** AS_ECHO and AS_ECHO_N unconditionally use ‘printf’.
This is substantially simpler, more reliable, and, in most cases,
faster than attempting to use ‘echo’ at all. However, if ‘printf’
is not a shell builtin, configure scripts will run noticeably
slower, and if ‘printf’ is not available at all, they will crash.
The only systems where this is known to be a problem are extremely
old, and unlikely to be able to handle modern C programs for other
reasons (e.g. not having a C90-compliant compiler at all).
*** Configure scripts require support for $( ... ) command substitution.
This POSIX shell feature is approximately the same age as
user-defined functions, but there do exist shells that support
functions and not $( ... ), such as Solaris 10 /bin/sh.
Configure scripts will automatically locate a shell that supports
this feature and re-execute themselves with it, if necessary, so
the new requirement should be transparent to most users.
In this release, most of Autoconf’s code still uses the older `...`
notation for command substitution.
*** AC_INIT now trims extra white space from its arguments.
For instance, AC_INIT([ GNU Hello ], [1.0]) will set PACKAGE_NAME
to “GNU Hello”.
*** Macros that take whitespace-separated lists as arguments
now always expand macros within those arguments.
Formerly, these macros would *usually* expand those arguments, but
the behavior was not reliable nor was it consistent between autoconf
and autoheader.
Macro expansion within these arguments is deprecated; if expansion
changes the list, a warning in the “obsolete” category will be
emitted. Note that ‘dnl’ is a macro. Putting ‘dnl’ comments inside
any argument to an Autoconf macro is, in general, only supported
when that argument takes more Autoconf code (e.g. the ACTION-IF-TRUE
argument to AC_COMPILE_IFELSE).
The affected macros are AC_CHECK_FILES, AC_CHECK_FUNCS,
AC_CHECK_FUNCS_ONCE, AC_CHECK_HEADERS, AC_CHECK_HEADERS_ONCE,
AC_CONFIG_MACRO_DIRS, AC_CONFIG_SUBDIRS, and AC_REPLACE_FUNCS.
*** AC_FUNC_VFORK no longer ignores a signal-handling bug in Solaris 2.4.
This bug was being ignored because Emacs wanted to use ‘vfork’ on
Solaris 2.4 anyway, but current versions of Emacs have dropped
support for Solaris 2.4. Most programs will want to avoid ‘vfork’
on this OS because of this bug.
*** AC_FUNC_STRERROR_R assumes strerror_r is unavailable if it’s not declared.
The fallback technique it used to probe strerror_r’s return type
when the function was present in the C library, but not declared by
<string.h>, was fragile and did not work at all when cross-compiling.
The systems where this fallback was necessary were all obsolete.
Programs that use AC_FUNC_STRERROR_R should make sure to test the
preprocessor macro HAVE_DECL_STRERROR_R before using strerror_r at all.
*** AC_OPENMP can’t be used if you have files named ‘mp’ or ‘penmp’.
Autoconf will now issue an error if AC_OPENMP is used in a configure
script that’s in the same directory as a file named ‘mp’ or ‘penmp’.
Configure scripts that use AC_OPENMP will now error out upon
encountering files with these names in their working directory
(e.g. when the build directory is separate from the source directory).
If you have files with these names at the top level of your source
tree, we recommend either renaming them or moving them into a
subdirectory. See the documentation of AC_OPENMP for further
explanation.
** New features
*** Configure scripts now support a ‘--runstatedir’ option.
This defaults to ‘${localstatedir}/run’. It can be used, for
instance, to place per-process temporary runtime files (such as pid
files) into ‘/run’ instead of ‘/var/run’.
*** autoreconf will now run gtkdocize and intltoolize when appropriate.
*** autoreconf now recognizes AM_GNU_GETTEXT_REQUIRE_VERSION.
This macro can be used with gettext 0.19.6 or later to specify
a *minimum* version requirement for gettext, instead of the *fixed*
version requirement specified by AM_GNU_GETTEXT_VERSION.
*** autoheader handles secondary config headers better.
It is no longer necessary to duplicate AC_DEFINE templates in the
main configuration header for autoheader to notice them.
*** AC_PROG_CC now enables C2011 mode if the compiler supports it.
If not, it will fall back to C99 and C89, as before. Similarly,
AC_PROG_CXX now enables C++2011 if available, falling back on C++98.
*** New macro AC_C__GENERIC tests for C2011 _Generic support.
*** AC_C_VARARRAYS has been aligned with C2011.
It now defines __STDC_NO_VLA__ if variable-length arrays are not
supported but the compiler does not define __STDC_NO_VLA__.
For backward compatibility with Autoconf 2.61-2.69 AC_C_VARARRAYS
still defines HAVE_C_VARARRAYS, but this result macro is obsolescent.
*** New macro AC_CONFIG_MACRO_DIRS.
This macro can be used more than once and accepts a list of
directories to search for local M4 macros. With Automake 1.13 and
later, use of this macro eliminates a reason to use ACLOCAL_AMFLAGS
in Makefile.am.
The older AC_CONFIG_MACRO_DIR, which could only be used once, is
still supported but considered deprecated.
*** AC_USE_SYSTEM_EXTENSIONS knows about more extensions to enable.
System extensions will now be enabled on HP-UX, macOS, and MINIX.
Optional ISO C library components (e.g. decimal floating point) will
also be enabled.
*** New compatibility macro AC_CHECK_INCLUDES_DEFAULT.
This macro runs the checks normally performed as a side-effect by
AC_INCLUDES_DEFAULT, if they haven’t already been done. Autoupdate
will replace certain obsolete constructs, whose only remaining
useful effect is to trigger those checks, with this macro. It is
unlikely to be useful otherwise.
*** AC_REQUIRE_AUX_FILE has been improved.
Configure scripts now check, on startup, for the availability of all
the aux files that were mentioned in an AC_REQUIRE_AUX_FILE
invocation. This should help prevent certain classes of packaging
errors.
Also, it is no longer necessary for third-party macros that use
AC_REQUIRE_AUX_FILE to mention AC_CONFIG_AUX_DIR_DEFAULT. However,
if you are using AC_CONFIG_AUX_DIR_DEFAULT *without* also using
AC_REQUIRE_AUX_FILE, please start using AC_REQUIRE_AUX_FILE to
specify the aux files you actually need, so that the check can be
effective.
*** AC_PROG_LEX has an option to not look for yywrap.
AC_PROG_LEX now takes one argument, which may be either ‘yywrap’ or
‘noyywrap’. If it is ‘noyywrap’, AC_PROG_LEX will only set LEXLIB
to ‘-lfl’ or ‘-ll’ if a scanner that defines both main and yywrap
itself still needs something else from that library. On the other
hand, if it is ‘yywrap’, AC_PROG_LEX will fail (setting LEX to ‘:’
and LEXLIB to nothing) if it can’t find a library that defines yywrap.
In the absence of arguments, AC_PROG_LEX’s behavior is bug-compatible
with 2.69, which did neither of the above things (see the manual for
details). This mode is deprecated.
We encourage all programs that use AC_PROG_LEX to use the new
‘noyywrap’ mode, and to define yywrap themselves, or use %noyywrap.
The yywrap function in lib(f)l is trivial, and self-contained
scanners are easier to work with.
** Obsolete features and new warnings
*** Use of the long-deprecated name ‘configure.in’ for the autoconf
input file now elicits a warning in the “obsolete” category.
*** Use of the undocumented internal shell variables $as_echo and
$as_echo_n now elicits a warning in the “obsolete” category.
The macros AS_ECHO and AS_ECHO_N should be used instead.
*** autoconf will now issue warnings (in the “syntax” category)
if the input file is missing a call to AC_INIT and/or AC_OUTPUT.
*** autoconf will now issue warnings (in the “syntax” category)
for a non-literal URL argument to AC_INIT, and for a TARNAME
argument to AC_INIT which is either non-literal or contains
characters that should not be used in file names (e.g. ‘*’).
*** AC_PROG_CC_STDC, AC_PROG_CC_C89, AC_PROG_CC_C99 are now obsolete.
Applications should use AC_PROG_CC.
*** AC_HEADER_STDC and AC_HEADER_TIME are now stubs.
They still define the C preprocessor macros STDC_HEADERS and
TIME_WITH_SYS_TIME, respectively, but they no longer check for the
ancient, non-ISO-C90 compliant systems where formerly those macros
would not be defined. Autoupdate will remove them.
These macros were already labeled obsolete in the manual.
*** AC_DIAGNOSE, AC_FATAL, AC_WARNING, and _AC_COMPUTE_INT are now
replaced with modern equivalents by autoupdate.
These macros were already labeled obsolete in the manual.
*** AC_CONFIG_HEADER is now diagnosed as obsolete, and replaced with
AC_CONFIG_HEADERS by autoupdate.
This macro has been considered obsolete for many years and was not
documented at all.
*** The macro AC_OBSOLETE is obsolete.
Autoupdate will replace it with m4_warn([obsolete], [explanation]).
If possible, macros using AC_OBSOLETE should be converted to use
AU_DEFUN or AU_ALIAS instead, which enables autoupdate to replace
them, but this has to be done by hand and is not always possible.
This macro has been considered obsolete for many years, but was not
officially declared as such.
*** Man pages for config.guess and config.sub are no longer provided.
They were moved to the master source tree for config.guess and
config.sub.
** Notable bug fixes
*** Compatible with current Automake, Libtool, Perl, Texinfo, and shells.
All of autoconf’s tools and generated scripts, and the build process
and testsuite for autoconf itself, have been tested to work
correctly with current versions of Automake, Libtool, Perl, Texinfo,
bash, ksh93, zsh, and FreeBSD and NetBSD /bin/sh.
Generated configure scripts are expected to work reliably with an
even wider variety of shells, including BusyBox sh and various
proprietary Unixes’ /bin/sh, as long as they are minimally compliant
with the Unix95 shell specification. Notably, support for
shell-script functions and the ‘printf’ builtin are required.
*** Checks compatible with current language standards and compilers.
Many individual macros have been improved to accommodate changes in
recent versions of the C and C++ language standards, and new
features and quirks of commonly used compilers (both free and
proprietary).
*** Improved support for cross compilation.
Many individual macros have been improved to produce more accurate
results when cross-compiling.
*** Improved robustness against unusual build environments.
Many bugs have been fixed where generated configure scripts would
fail catastrophically under unusual conditions, such as stdout being
closed, or $TMPDIR not being an absolute path, or the root directory
being mentioned in $PATH.
*** AC_CHECK_FUNCS_ONCE and AC_CHECK_HEADERS_ONCE now support multiple
programming languages. They no longer perform all checks in the
language active upon the first use of the macro.
*** AC_CHECK_DECL and AC_CHECK_DECLS will now detect missing declarations for
library functions that are also Clang compiler builtins.
*** AC_PATH_X and AC_PATH_XTRA don’t search for X11 when cross-compiling.
Libraries and headers found by running xmkmf or searching /usr/X11,
/usr/X11R7, etc. are likely to belong to a native X11 installation
for the build machine and to be inappropriate for cross compilation.
To cross-compile programs that require X11, we recommend putting the
headers and libraries for the host system in your cross-compiler’s
default search paths. Alternatively, use configure’s --x-includes
and --x-libraries command line options to tell it where they are.
*** AS_IF’s if-false argument may be empty after macro expansion.
This long-standing limitation broke configure scripts that used
macros in this position that emitted shell code in 2.69 but no
longer do, so we have lifted it.
*** AC_HEADER_MAJOR detects the location of the major, minor, and
makedev macros correctly under glibc 2.25 and later.
*** AC_FC_LINE_LENGTH now documents the maximum portable length of
“unlimited” Fortran source code lines to be 250 columns, not 254.
*** AC_INIT and AS_INIT no longer embed (part of) the path to the
source directory in generated files.
We believe this was the only case where generated file contents
could change depending on the environment outside the source tree
itself. If you find any other cases please report them as bugs.
*** config.log properly escapes arguments in the header comment.
*** config.status --config output is now quoted in a more readable fashion.
** Autotest enhancements
*** Autotest provides a new macro AT_DATA_UNQUOTED, similar to AT_DATA
but processing variable substitutions, command substitutions and
backslashes in the contents argument.
*** AC_CONFIG_TESTDIR will automatically pass EXEEXT to a testsuite (via
the atconfig file).
*** AT_TESTED arguments can use variable or command substitutions, including
in particular $EXEEXT
*** New macros AT_PREPARE_TESTS, AT_PREPARE_EACH_TEST, and AT_TEST_HELPER_FN.
These provide an official way to define testsuite-specific
initialization code and shell functions.
* Noteworthy changes in release 2.69 (2012-04-24) [stable]
** Autoconf now requires perl 5.6 or better (but generated configure
scripts continue to run without perl).
* Noteworthy changes in release 2.68b (2012-03-01) [beta]
Released by Eric Blake, based on git versions 2.68.*.
** Autoconf-generated configure scripts now unconditionally re-execute
themselves with $CONFIG_SHELL, if that's set in the environment.
** The texinfo documentation no longer specifies "front-cover" or
"back-cover" texts, so that it may now be included in Debian's
"main" section.
** Support for the Go programming language has been added. The new macro
AC_LANG_GO sets variables GOC and GOFLAGS.
** AS_LITERAL_IF again treats '=' as a literal. Regression introduced in
2.66.
** The macro AS_EXECUTABLE_P, present since 2.50, is now documented.
** Macros
- AC_PROG_LN_S and AS_LN_S now fall back on 'cp -pR' (not 'cp -p') if 'ln -s'
does not work. This works better for symlinks to directories.
- New macro AC_HEADER_CHECK_STDBOOL.
- New and updated macros for Fortran support:
AC_FC_CHECK_BOUNDS to enable array bounds checking
AC_F77_IMPLICIT_NONE and AC_FC_IMPLICIT_NONE to disable implicit integer
AC_FC_MODULE_EXTENSION to compute the Fortran 90 module name extension
AC_FC_MODULE_FLAG for the Fortran 90 module search path flag
AC_FC_MODULE_OUTPUT_FLAG for the Fortran 90 module output directory flag
AC_FC_PP_SRCEXT for preprocessed Fortran source files extensions
AC_FC_PP_DEFINE for the Fortran preprocessor define flag
* Noteworthy changes in release 2.68 (2010-09-22) [stable]
Released by Eric Blake, based on git versions 2.67.*.
** AC_MSG_ERROR (and AS_ERROR) can once again be followed immediately by
'dnl'. Regression introduced in 2.66.
** AC_INIT again allows URLs with '?' for its BUG-REPORT argument.
Regression introduced in 2.66.
** AC_REPLACE_FUNCS again allows a non-literal argument, such as a shell
variable that expands to a list of functions to check. Regression
introduced in 2.66.
** AT_BANNER() with empty argument will cause visual separation from previous
test category.
** The macros AC_PREPROC_IFELSE, AC_COMPILE_IFELSE, AC_LINK_IFELSE, and
AC_RUN_IFELSE now warn if the first argument failed to use
AC_LANG_SOURCE or AC_LANG_PROGRAM to generate the conftest file
contents. A new macro AC_LANG_DEFINES_PROVIDED exists if you have
a compelling reason why you cannot use AC_LANG_SOURCE but must
avoid the warning.
** The macro m4_define_default is now documented.
** Symlinked config.cache files are supported; configure now tries to
update non-symlinked cache files atomically, so that concurrent configure
runs do not leave behind broken cache files. It is still unspecified
which subset or union of results is cached though.
** Autotest testsuites should not contain long text lines any more, and be
portable even when very many test groups are used.
** AT_CHECK semantics with respect to the Autotest variable $at_status and
shell execution environment of the arguments are documented now.
** AC_FC_LIBRARY_LDFLAGS now tolerates output from newer gfortran.
** Newly obsolete macros
The following macros have been marked obsolete. New programs
should use the corresponding Gnulib modules. Gnulib not only
detects a larger set of portability problems with these functions,
but also provides complete workarounds.
AC_FUNC_ERROR_AT_LINE AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK
AC_FUNC_MKTIME AC_FUNC_STRTOD
* Major changes in Autoconf 2.67 (2010-07-21) [stable]
Released by Eric Blake, based on git versions 2.66.*.
** AC_CONFIG_SUBDIRS with more than one subdirectory at a time works again.
Regression introduced in 2.66.
** AC_CHECK_SIZEOF of a pointer type works again. Regression introduced in
2.66.
** New macro AC_FC_LINE_LENGTH to accept long Fortran source code lines.
** AC_PREPROC_IFELSE now keeps the preprocessed output in the conftest.i
file for inspection by the commands in the ACTION-IF-TRUE argument.
** AC_INIT again allows parentheses and other characters that are literal
in single- or double-quoted strings, and in quoted and unquoted
here-documents, for its PACKAGE and VERSION arguments. Regression
introduced in 2.66.
** autoreconf passes warning flags to new enough versions of aclocal.
** Running an Autotest testsuite in parallel mode no longer triggers a
race condition that could cause the testsuite run to end early,
fixing a sporadic failure in autoconf's own testsuite. Bug present
since introduction of parallel tests in 2.63b.
* Major changes in Autoconf 2.66 (2010-07-02) [stable]
Released by Eric Blake, based on git versions 2.65.*.
** AC_FUNC_MMAP works in C++ mode again. Regression introduced in 2.65.
** Use of m4_divert without a named diversion now issues a syntax warning,
since it is seldom right to change diversions behind autoconf's back.
** The macros AC_TYPE_INT8_T, AC_TYPE_INT16_T, AC_TYPE_INT32_T, and
AC_TYPE_INT64_T work again. Regression introduced in 2.65.
** AC_PROG_INSTALL correctly uses 'shtool' again. Regression introduced
in 2.64.
** Autoconf should work on EBCDIC hosts.
** AC_CHECK_DECL and AC_CHECK_DECLS accept optional function argument types
for overloaded C++ functions.
** AS_SET_CATFILE accepts nonliterals in its variable name argument now.
** Autotest testsuites accept an option --recheck to rerun tests that
failed or passed unexpectedly during the last non-debug testsuite run.
** AC_ARG_ENABLE and AC_ARG_WITH now also accept '+' signs in '--enable-*'
and '--with-*' arguments, converting them to underscores for the variable
names.
** In configure scripts, loading CONFIG_SITE no longer searches PATH,
and problems in loading the configuration site files are diagnosed.
** Autotest testsuites may optionally provide colored test results.
** The previously undocumented Autotest macros AT_ARG_OPTION and
AT_ARG_OPTION_ARG have seen bug fixes and are documented now.
AT_ARG_OPTION has been changed in that the negative of a long option
--OPTION is now --no-OPTION rather than --noOPTION.
** The macro AS_LITERAL_IF is slightly more conservative; text
containing shell quotes are no longer treated as literals.
Furthermore, a new macro, AS_LITERAL_WORD_IF, adds an additional
level of checking that no whitespace occurs in literals.
** The macros AS_TR_SH and AS_TR_CPP no longer expand their results.
** The following macros are now documented:
AS_BOX
** New macro AC_FC_FIXEDFORM to accept fixed-form Fortran.
* Major changes in Autoconf 2.65 (2009-11-21) [stable]
Released by Eric Blake, based on git versions 2.64.*.
** Autoconf is now licensed under the General Public License version 3
or later (GPLv3+). As with earlier versions, the license includes
an exception clause so that you may release a configure script
generated by autoconf under the license of your own program.
** New macros to support Objective C++.
AC_PROG_OBJCXX AC_PROG_OBJCXXCPP
** The following undocumented autoconf macros, removed in Autoconf 2.64,
have been reinstated:
AH_CHECK_HEADERS
These macros are present only for backwards compatibility purposes.
** The macro AC_LANG_COMPILER no longer fails on embedded systems that
lack fopen in the C library, such as AVR or RTEMS (regression
introduced in 2.64).
** The AC_FC_FREEFORM macro no longer suffers from a whitespace bug that
made it fail with some Fortran compilers (regression introduced in
2.64).
** The AC_TYPE_UINT64_T and AC_TYPE_INT64_T macros have been fixed to no
longer mistakenly select a 32-bit type on some compilers (bug present
since macros were introduced in 2.59c).
** The AC_FUNC_MMAP macro has been fixed to be portable to systems like
Cygwin (bug present since macro was introduced in 2.0).
** The following documented autotest macros are new:
AT_CHECK_EUNIT
** The following m4sugar macros now quote their expansion:
m4_toupper m4_tolower
** The following m4sugar macros are new:
m4_escape
** The m4sugar macro m4_text_wrap now copes with embedded quoting without
requiring quadrigraphs. For uses like AC_ARG_VAR([a], [[b c]]),
this gives the intuitive behavior of "[b c]" in the output (2.63
gave the output of "[b], [c]", and 2.64 encountered a failure).
** The '$tmp' temporary directory used in config.status is documented for
public use now.
** config.status now provides a --config option to produce the configuration.
** Many cache variables used by Autoconf's macros are now documented.
** Configure scripts work better on DJGPP by avoiding a bug present in
the DJGPP port of bash 2.04 in handling 'return' in a shell
function (regression introduced in 2.64).
* Major changes in Autoconf 2.64 (2009-07-26) [stable]
Released by Eric Blake, based on git versions 2.63b.*.
** Autoconf now requires GNU M4 1.4.6 or later. Earlier versions of M4
have a bug in regular expression handling that interferes with some
of the speedups provided since Autoconf 2.63. GNU M4 1.4.13 or
later is recommended.
** AS_IF and AS_CASE have been taught to avoid syntax errors even when
given arguments that expand to just whitespace.
** The following documented autoconf macros are new:
AC_ERLANG_SUBST_ERTS_VER
** The autoheader tool now understands m4 macro arguments passed to
AC_DEFINE and AC_DEFINE_UNQUOTED.
** Ensure AT_CHECK can support commands that include a # given with
proper m4 quoting. For shell comments, this is a new feature; for
non-shell comments, this fixes a regression introduced in 2.63b.
Additionally, AT_CHECK correctly supplies shell escapes for
metacharacters occurring in m4 macro expansions within the expected
stdout and stderr parameters.
** The macro AT_CHECK now understands the concept of hard failure. If
a test exits with an unexpected status 99, cleanup actions for the
test are inhibited and the test is treated as a failure regardless
of AT_XFAIL_IF. It also understands the new directives
ignore-nolog, stdout-nolog, and stderr-nolog.
** The following documented autotest macros are new:
AT_CHECK_UNQUOTED AT_FAIL_IF AT_SKIP_IF
** The following documented m4sugar macros are new:
m4_argn m4_copy_force m4_default_nblank m4_default_nblank_quoted
m4_ifblank m4_ifnblank m4_rename_force
** The autoconf testsuite now exercises all Erlang macros.
* Major changes in Autoconf 2.63b (2009-03-31) [beta]
Released by Eric Blake, based on git versions 2.63.*.
** The manual is now shipped under the terms of the GNU FDL 1.3.
** AC_REQUIRE now detects the case of an outer macro which first expands
then later indirectly requires the same inner macro. Previously,
this case led to silent out-of-order expansion (bug present since
2.50); it now issues a syntax warning, and duplicates the expansion
of the inner macro to guarantee dependencies have been met. See
the manual for advice on how to refactor macros in order to avoid
the bug in earlier autoconf versions and avoid increased script
size in the current version.
** AC_DEFUN_ONCE has improved semantics. Previously, a macro declared
with AC_DEFUN_ONCE warned on a second invocation; and out-of-order
expansion was still possible. Now, dependencies are guaranteed,
and subsequent invocations are a silent no-op. This makes
AC_DEFUN_ONCE an ideal macro for silencing AC_REQUIRE warnings.
** The following macros are now defined with AC_DEFUN_ONCE. This means
a subtle change in semantics; previously, an AC_DEFUN macro could
expand one of these macros multiple times or surround the macro
inside shell conditional text to bypass the effects of these
macros, but now the macro will expand exactly once, and prior to
the start of any enclosing AC_DEFUN macro:
AC_CANONICAL_BUILD AC_CANONICAL_HOST AC_CANONICAL_TARGET
AC_HEADER_ASSERT AC_PROG_INSTALL AC_PROG_MKDIR_P
AC_USE_SYSTEM_EXTENSIONS
** AC_LANG_ERLANG works once again (regression introduced in 2.61a).
** AC_HEADER_ASSERT is fixed so that './configure --enable-assert' no
longer mistakenly disables assertions.
** AC_INIT now takes an optional fifth parameter that can be used to
set AC_PACKAGE_URL, a URL for the package's home page; the URL is
used in 'configure --help' and is also available via AC_DEFINE.
** Autotest testsuites accept an option --jobs[=N] for parallel testing.
This feature is still in testing, and may not work on every
platform, help in improving it would be appreciated.
** Autotest testsuites do not attempt to write startup error messages
to the log file before that is opened (regression introduced in 2.63).
** Configure scripts now use shell functions. This feature leads to
smaller configure files and faster execution.
** Present But Cannot Be Compiled: Autoconf will now proceed with
the compiler's result if a header is present but cannot be compiled.
The warning is still printed, and you should really fix it by
providing a fourth parameter to AC_CHECK_HEADER/AC_CHECK_HEADERS.
** Autoreconf added aclocal to the set of programs affected by the
'autoreconf -I dir' option.
** The following documented m4sugar macros are new:
m4_chomp m4_chomp_all m4_cleardivert m4_curry m4_default_quoted
m4_esyscmd_s m4_map_args m4_map_args_pair m4_map_args_sep
m4_map_args_w m4_set_map m4_set_map_sep m4_stack_foreach
m4_stack_foreach_lifo m4_stack_foreach_sep
m4_stack_foreach_sep_lifo
** The following m4sugar macros are documented now, but in some cases
with slightly different semantics than what the previous
undocumented version had:
m4_copy m4_dumpdefs m4_rename m4_version_prereq
** The m4sugar macro m4_expand has been taught to handle unterminated
comments and shell case statements. As a result, it is used
internally in more places, such as AC_DEFINE and AT_CHECK. Most
uses of AC_DEFINE and AT_CHECK should not behave any differently;
however, it may be necessary to add double-quoting around
unbalanced '(' where single-quoting used to be sufficient.
** The following documented m4sh macros are new:
AS_INIT_GENERATED AS_LINENO_PREPARE AS_ME_PREPARE AS_SET_STATUS
AS_VAR_APPEND AS_VAR_ARITH AS_VAR_COPY
** The following m4sh macros are documented now, but in some cases
with slightly different semantics than what the previous
undocumented version had:
AS_ECHO AS_ECHO_N AS_ESCAPE AS_EXIT AS_LITERAL_IF AS_UNSET
AS_VAR_IF AS_VAR_POPDEF AS_VAR_PUSHDEF AS_VAR_SET AS_VAR_SET_IF
AS_VAR_TEST_SET AS_VERSION_COMPARE
** The m4sh macros AS_IF and AS_CASE can now be used in shell lists.
The responsibility for supplying a trailing newline now belongs to
the call site, but since most users did not add dnl, this generally
results in fewer empty lines in configure.
* Major changes in Autoconf 2.63 (2008-09-09) [stable]
Released by Eric Blake, based on git versions 2.62.*.
** AC_C_BIGENDIAN does not mistakenly report "universal" for some
bigendian hosts, a regression introduced with universal binary
support in 2.62.
** AC_PATH_X now includes /lib64 and /usr/lib64 in its list of default
library directories.
** AC_USE_SYSTEM_EXTENSIONS no longer conflicts with an external
AC_DEFINE([__EXTENSIONS__]). This fixes a regression introduced in
2.62 when using macros such as AC_AIX that were made obsolete in
favor of the more portable AC_USE_SYSTEM_EXTENSIONS.
** AC_CHECK_TARGET_TOOLS is usable in the non-cross-compile case.
** Newly obsolete macros
The following macro has been marked obsolete, since current porting
targets can safely assume C89 semantics that signal handlers return
void. We have no current plans to remove the macro.
AC_TYPE_SIGNAL
** The macros m4_map and m4_map_sep now ignore any list elements
consisting of just empty quotes, and m4_map_sep now expands its
separator. This fixes a regression in 2.62 when these macros were
first documented, for the sake of clients expecting the semantics
that these macros had prior to that time. The new macros m4_mapall
and m4_mapall_sep, along with extra quoting of the separator, can
be used to get the semantics that m4_map_sep had in 2.62.
** Clients of m4_expand, such as AS_HELP_STRING and AT_SETUP, can now
handle properly quoted but otherwise unbalanced parentheses (for
some macros, this fixes a regression in 2.62).
** Two new quadrigraphs have been introduced: @{:@ for (, and @:}@ for ),
allowing the output of unbalanced parentheses in more contexts.
** The following m4sugar macros are new:
m4_cleardivert m4_joinall m4_mapall m4_mapall_sep m4_reverse
m4_set_add m4_set_add_all m4_set_contains m4_set_contents
m4_set_delete m4_set_difference m4_set_dump m4_set_empty
m4_set_foreach m4_set_intersection m4_set_list m4_set_listc
m4_set_remove m4_set_size m4_set_union
** The following m4sugar macros now accept multiple arguments, as is the
case with underlying m4:
m4_defn m4_popdef m4_undefine
** The following m4sugar macros now guarantee linear scaling; they
previously had linear scaling with m4 1.6 but quadratic scaling
when using m4 1.4.x. All macros built on top of these also gain
the scaling improvements.
m4_bmatch m4_bpatsubsts m4_case m4_cond m4_do m4_dquote_elt
m4_foreach m4_join m4_list_cmp m4_map m4_map_sep m4_max
m4_min m4_shiftn
** AT_KEYWORDS once again performs expansion on its argument, such that
AT_KEYWORDS([m4_if([$1], [], [default])]) no longer complains about
the possibly unexpanded m4_if [regression introduced in 2.62].
** Config header templates '#undef UNDEFINED /* comment */' do not lead to
nested comments any more; regression introduced in 2.62.
* Major changes in Autoconf 2.62 (2008-04-05) [stable]
Released by Eric Blake, based on git versions 2.61a.*.
** Many optimizations have been applied to make overall execution faster.
** Autotest now makes use of shell functions.
** config.status now uses awk instead of sed also for config headers.
- As a side effect, AC_DEFINE and AC_DEFINE_UNQUOTED now handle multi-line
values, i.e., backslash-newline combinations are handled correctly.
Further, for config headers, the total size of values is not limited by
the POSIX length limit of text lines any more, only each single line.
** New config variable 'top_build_prefix'.
** New Autoconf macros:
AC_AUTOCONF_VERSION AC_OPENMP AC_PATH_PROGS_FEATURE_CHECK
** AC_C_BIGENDIAN now supports universal binaries a la Mac OS X.
** AC_C_RESTRICT now prefers to #define 'restrict' to a variant spelling
like '__restrict' if the variant spelling is available, as this is
more likely to work when mixing C and C++ code.
** AC_CHECK_ALIGNOF's type argument T is now documented better: it must
be a string of tokens such that "T y;" is a valid member declaration
in a struct.
** AC_CHECK_SIZEOF now accepts objects as well as types: the general rule
is that sizeof (X) works, then AC_CHECK_SIZEOF (X) should work.
** AC_CHECK_TYPE and AC_CHECK_TYPES now work on any C type-name; formerly,
they did not work for function types. In C++, they now work on any
type-id that can be the operand of sizeof; this is similar to C,
except it excludes anonymous struct and union types. Formerly,
some (but not all) C++ types involving anonymous struct and union
were accepted, though this was not documented.
** AC_CONFIG_LINKS now prefers to link against files in the build tree
if found, and it works to link against a file of the same name in
the source tree, even if both trees coincide.
** AC_INIT no longer alters $@; regression introduced in 2.60.
** AC_USE_SYSTEM_EXTENSIONS now defines _ALL_SOURCE for Interix platforms.
** AS_HELP_STRING no longer underquotes its first argument; it also handles
the case where the first argument contains single-quoted commas.
For example, "AS_HELP_STRING([-a, [--arg[=foo]]], [bar])" produces:
" -a, --arg[=foo] bar"
Additionally, the macro now takes two additional arguments,
indent-column and wrap-column; these should not normally be needed,
but can be used to fine-tune how the output text is wrapped.
** AC_PROG_INSTALL now requires an install program that can install multiple
files into a target directory.
** The command 'autoconf -' now correctly processes a file from stdin.
** 'autoreconf -m' now honors $MAKE.
** For all of the directory arguments for 'configure', such as '--prefix'
or '--bindir', trailing slashes are stripped. As an example, if
tab completion in the user's shell appends trailing slashes, the
command './configure --prefix=/usr/' will still result in an
expanded libdir value of /usr/lib, not /usr//lib.
** 'configure --help=recursive' now works in read-only trees and from
unconfigured build trees.
** If precious variables differ only in whitespace, then the cache consistency
check warns instead of fails, and reuses the old value.
** AT_BANNER is now documented.
** AT_SETUP now handles macro expansions properly when calculating line
length.
** Autotest now determines $srcdir correctly.
** Testsuites built by autotest now accept a -C/--directory=DIR option
to adjust the working directory prior to creating files.
** Autoconf now requires GNU M4 1.4.5 or later. Earlier versions of M4 have
a bug in macro tracing that interferes with the interaction between
Autoconf and Automake. GNU M4 1.4.11 or later is recommended. The
configure search for a working M4 is improved.
** For portability with the eventual M4 2.0, macros should no longer use
anything larger than $9 to refer to arguments.
** Documentation for m4sugar is improved.
- The following macros were previously available as undocumented
interfaces; the macros are now documented as stable interfaces.
__oline__ m4_assert m4_bmatch m4_bpatsubsts m4_car m4_case
m4_cdr m4_default m4_divert_once m4_divert_pop m4_divert_push
m4_divert_text m4_do m4_errprintn m4_fatal m4_flatten
m4_ifndef m4_ifset m4_ifval m4_ifvaln m4_location
m4_n m4_shiftn m4_strip m4_warn
- The following macros were previously available as undocumented
interfaces, but had bug fixes or semantic changes as part of this
release. Packages that relied on the undocumented behavior
should be analyzed to make sure they will still work with the
new documented behavior.
m4_cmp m4_list_cmp m4_join m4_map m4_map_sep m4_sign
m4_text_box m4_text_wrap m4_version_compare
- The m4_wrap macro used to have unspecified order, but now
guarantees FIFO order. m4_wrap_lifo was added to guarantee LIFO
order.
- Packages using the undocumented m4sugar macro m4_PACKAGE_VERSION
should consider using the new AC_AUTOCONF_VERSION instead.
- m4sugar macros that are not documented in the manual are still
deemed experimental, and should not be used outside of Autoconf.
** The m4sugar macros m4_append and m4_append_uniq, first documented in
2.60, have been fixed to treat both the string and the separator
arguments consistently with regards to quoting. Prior to this fix,
m4_append_uniq could mistakenly duplicate entries if the expansion
of the separator resulted in a different string (for example, if it
contained quotes, a comma, or a macro name). However, it means
that programs previously using
m4_append([name], [string], [[, ]])
are now using a four-character separator instead of the intended
comma and space. If you need portability to earlier versions of
Autoconf, you can insert the following snippet after AC_INIT but
before any other macro expansions, to enforce the new semantics:
m4_pushdef([m4_append], [m4_define([$1],
m4_ifdef([$1], [m4_defn([$1])[$3]])[$2])])
Additionally, m4_append_uniq now takes optional parameters that can
be used to take action depending on whether anything was appended,
and warns if a non-empty separator occurs within the string being
appended, since that can lead to duplicates.
** The following m4sugar macros are new:
m4_append_uniq_w m4_apply m4_combine m4_cond m4_count
m4_dquote_elt m4_echo m4_expand m4_ignore m4_make_list m4_max
m4_min m4_newline m4_shift2 m4_shift3 m4_unquote m4_wrap_lifo
** Warnings are now generated by default when an installer invokes
'configure' with an unknown --enable-* or --with-* option.
These warnings can be disabled with the new AC_DISABLE_OPTION_CHECKING
macro, or by invoking 'configure' with --disable-option-checking.
** Existing obsolete macros
The documentation for the following macros is adjusted to make it
more clear that they have previously been marked obsolete, as their
functionality can be accomplished by other macros. We have no
current plans to remove them from Autoconf.
AC_ENABLE AC_STRUCT_ST_BLKSIZE AC_STRUCT_ST_RDEV AC_WITH
** Newly obsolete macros
The following macros have been marked obsolete, as they only
perform a subset of AC_USE_SYSTEM_EXTENSIONS. We have no current
plans to remove them.
AC_AIX AC_GNU_SOURCE AC_ISC_POSIX AC_MINIX
** AC_C_LONG_DOUBLE is obsolescent.
The documentation now says that AC_C_LONG_DOUBLE is obsolescent: it
tests for problems that are so old that it is no longer of
practical importance on current systems. New programs need not use
AC_C_LONG_DOUBLE. We have no current plans to remove it.
** AC_DIAGNOSE, AC_WARNING, and AC_FATAL are obsolescent.
The documentation now favors the use of M4sugar macros m4_warn and
m4_fatal, since the naming makes it more obvious that the
diagnostics are associated with M4 expansion (ie. when running
'autoconf'), and offers less confusion with the AC_MSG_ERROR,
AC_MSG_FAILURE, and AC_MSG_WARN macros which manage diagnostics
when running 'configure'. We have no current plans to remove these
macros.
* Major changes in Autoconf 2.61a (2006-12-11)
** AC_FUNC_FSEEKO was broken in 2.61; it didn't make fseeko and ftello visible
on many platforms. This has been fixed.
** AC_FUNC_SETVBUF_REVERSED is now obsolete. It is still defined for backward
compatibility but it does nothing. The macro was already
obsolescent, as the last systems to have the problem were those
based on SVR2, which became obsolete in 1987. The macro had bugs
on some modern systems and could no longer be maintained reliably
due to lack of ancient systems to test it on.
** config.status now uses awk instead of sed for most substitutions, for speed.
- As a side effect multi-line values of substituted variables no
longer have a small limit in total size, though for portability
each line should not exceed the POSIX length limit for text lines.
- It is now documented that Makefile.in should not contain
overlapping variable occurrences, e.g., @VAR1@VAR2@.
Autoconf's behavior was always iffy in such cases, and the
awk implementation has changed the behavior.
** Many uses of 'echo' have been rewritten so that Autoconf-generated
scripts have fewer problems with strings or file names containing
embedded special characters such as backslash or leading "-". This
was implemented by using 'printf '%s\n' "$foo"' instead of 'echo
"$foo"' when printf works. Due to the implementation technique
used, Autoconf-generated scripts now run considerably more slowly
on ancient implementations lacking printf. However, this should
not be a problem, since Autoconf-generated scripts in practice
invariably find a more-modern shell these days.
* Major changes in Autoconf 2.61 (2006-11-17)
** New macros AC_C_FLEXIBLE_ARRAY_MEMBER, AC_C_VARARRAYS.
** AC_ARG_ENABLE and AC_ARG_WITH now allow '.' in feature and package names.
* Major changes in Autoconf 2.60b (2006-10-22)
** BIN_SH
Autoconf-generated shell scripts no longer export BIN_SH, due to
configuration hassles with this. Installers who need BIN_SH in
their environment should set it before invoking 'configure' and
'make'. As far as we know, this affects only Unixware installations.
** Obsolescent macros
The documentation now says that the following macros are obsolescent,
as they are superseded by Gnulib:
AC_FUNC_FNMATCH AC_FUNC_FNMATCH_GNU AC_FUNC_GETLOADAVG
AC_REPLACE_FNMATCH
New programs should use the Gnulib counterparts of these macros.
We have no current plans to remove them from Autoconf.
** AC_COMPUTE_INT no longer caches or reports results.
** AC_CHECK_DECL now also works with aggregate objects.
** AC_USE_SYSTEM_EXTENSIONS now defines _TANDEM_SOURCE for NonStop platforms.
** GNU M4 1.4.7 or later is now recommended.
** m4_mkstemp
New M4sugar macro, which is more secure than the POSIX M4 maketemp.
** m4_maketemp
Now an alias for m4_mkstemp.
* Major changes in Autoconf 2.60a (2006-08-25)
** GNU M4 1.4.6 or later is now recommended.
** The check for C99 now tests for varargs macros, as documented.
It also tests that the preprocessor supports 64-bit integers.
** Autoconf now uses constructs like "#ifdef HAVE_STDLIB_H" rather than
"#if HAVE_STDLIB_H", so that it now works with "gcc -Wundef -Werror".
** The functionality of the undocumented _AC_COMPUTE_INT is now provided
by a public and documented macro, AC_COMPUTE_INT. The parameters to the
two macros are different, so autoupdate will not change the old private name
to the new one. _AC_COMPUTE_INT may be removed in a future release.
** AC_TYPE_LONG_LONG_INT and AC_TYPE_UNSIGNED_LONG_LONG_INT now require
that long long types be at least 64 bits wide, as C99 and tradition
requires. Formerly, they accepted implementations of any width.
* Major changes in Autoconf 2.60
Released 2006-06-23, by Ralf Wildenhues.
** Autoconf no longer depends on whether m4wrap is FIFO (as Posix requires)
or LIFO (as in GNU M4 1.4.x). GNU M4 2.0 is expected to conform to Posix
here, so m4wrap/m4_wrap users should no longer depend on LIFO behavior.
** Provide a way to turn off warnings about the changed directory variables.
* Major changes in Autoconf 2.59d
Released 2006-06-05, by Ralf Wildenhues.
** GNU make now recommended for VPATH builds
INSTALL now suggests VPATH builds (e.g., "sh ../srcdir/configure")
only if you use GNU make. In practice, other 'make' implementations
have too many subtle incompatibilities in their support for VPATH.
Many packages (including Autoconf itself) are portable to other
'make' implementations, but some packages are not, and recommending
GNU make keeps the installation instructions simpler.
** Even more safety checks for the new Directory variables:
Warn about suspicious '${datarootdir}' found in config files output.
** AC_TRY_COMMAND, AC_TRY_EVAL, ac_config_guess, ac_config_sub, ac_configure
These never-documented macros and variables have been marked with
comments saying that they may be removed in a future release,
because their use can lead to unintended code being executed.
If you need functionality that only these macros or variables
currently supply, please write bug-autoconf@gnu.org.
** AC_SUBST, AC_DEFINE
Literal arguments to these are passed to m4_pattern_allow now.
** AC_PROG_CC_STDC
Passing 'ac_cv_prog_cc_stdc=no' to 'configure' now sets ac_cv_prog_cc_c99
and ac_cv_prog_cc_c89 to 'no' as well, for backward compatibility with
obsolete K&R tests in the Automake test suite.
** AC_PROG_CXX_C_O
New macro.
** AC_PROG_MKDIR_P
New macro.
** AS_MKDIR_P
Now more robust with special characters in file names, or when
multiple processes create the same directory at the same time.
** Obsolescent macros
The documentation now says that the following macros are obsolescent:
they test for problems that are so old that they are no longer of
practical importance on current systems.
AC_C_BACKSLASH_A AC_FUNC_MEMCMP AC_HEADER_DIRENT
AC_C_CONST AC_FUNC_SELECT_ARGTYPES AC_HEADER_STAT
AC_C_PROTOTYPES AC_FUNC_SETPGRP AC_HEADER_STDC
AC_C_STRINGIZE AC_FUNC_SETVBUF_REVERSED AC_HEADER_SYS_WAIT
AC_C_VOLATILE AC_FUNC_STAT AC_HEADER_TIME
AC_FUNC_CLOSEDIR_VOID AC_FUNC_STRFTIME AC_ISC_POSIX
AC_FUNC_GETPGRP AC_FUNC_UTIME_NULL AC_PROG_GCC_TRADITIONAL
AC_FUNC_LSTAT AC_FUNC_VPRINTF AC_STRUCT_TM
New programs need not use these macros. We have no current plans to
remove them.
** autoreconf
For compatibility with future Libtool 2.0, autoreconf will invoke
libtoolize with the option '--ltdl' now, if LT_CONFIG_LTDL_DIR is
used.
* Major changes in Autoconf 2.59c
Released 2006-04-12, by Ralf Wildenhues.
** The configure command now redirects standard input from /dev/null,
to help avoid problems with subsidiary commands that might mistakenly
read standard input. AS_ORIGINAL_STDIN_FD points to the original
standard input before this redirection, if you really want configure to
read from standard input.
** Directory variables adjusted to recent changes in the GNU Coding Standards.
The following directory variables are new:
datarootdir read-only architecture-independent data root [PREFIX/share]
localedir locale-specific message catalogs [DATAROOTDIR/locale]
docdir documentation root [DATAROOTDIR/doc/PACKAGE]
htmldir html documentation [DOCDIR]
dvidir dvi documentation [DOCDIR]
pdfdir pdf documentation [DOCDIR]
psdir ps documentation [DOCDIR]
The following variables have new default values:
datadir read-only architecture-independent data [DATAROOTDIR]
infodir info documentation [DATAROOTDIR/info]
mandir man documentation [DATAROOTDIR/man]
This means that if you use any of '@datadir@', '@infodir@', or
'@mandir@' in a file, you will have to ensure '${datarootdir}' is
defined in this file. As a temporary measure, if any of those are
found but no mention of 'datarootdir', the substitutions will be
replaced with values that do not contain '${datarootdir}', and a
warning will be issued.
** @top_builddir@ is now a dir name: it is always nonempty and doesn't have
a trailing slash. Similar change will be made to ac_top_builddir in a
future release; the old style value, which matches (../)*, is (and will
continue to be) available as ac_top_build_prefix.
** AC_C_TYPEOF
New macro to check for support of 'typeof' syntax a la GNU C.
** AC_CHECK_DECLS_ONCE, AC_CHECK_FUNCS_ONCE, AC_CHECK_HEADERS_ONCE
New "once-only" variants of commonly-used macros, to make 'configure'
smaller and faster in common cases.
** AC_FUNC_STRTOLD
New macro to check for strtold with C99 semantics.
** AC_HEADER_ASSERT
New macro that lets builder disable assertions at 'configure'-time.
** AC_PATH_X
Now checks for X11/Xlib.h and XrmInitialize (X proper) rather than
X11/Intrinsic.h and XtMalloc (Xt).
** AC_PRESERVE_HELP_ORDER
New macro that causes 'configure' to display help strings for AC_ARG_ENABLE
and AC_ARG_WITH arguments in one region, in the order defined. The default
behavior is to group options of each classes separately.
** AC_PROG_CC, AC_PROG_CXX
No longer automatically arrange to declare the 'exit' function of C,
when a C++ compiler is used. Standard Autoconf macros no longer use
'exit', so this is no longer an issue for them. If you use C++, and
want to call 'exit', you'll have to arrange for its declaration
yourself. But we now suggest you return from 'main' instead.
** AC_PROG_CC_C89, AC_PROG_CC_C99
New macros for ISO C99 support. AC_PROG_CC_C89 and AC_PROG_CC_C99
check for ANSI C89 and ISO C99 support respectively.
** AC_PROG_CC_STDC
Has been unobsoleted, and will check if the compiler supports ISO
C99, falling back to ANSI C89 if not. ac_cv_prog_cc_stdc is
retained for backwards compatibility, assuming the value of
ac_cv_prog_cc_c99 or ac_cv_prog_cc_c89 (whichever is valid, in
that order).
** AC_STRUCT_DIRENT_D_INO, AC_STRUCT_DIRENT_D_TYPE
New macros for checking commonly-used members of struct dirent.
** AC_SUBST
The substituted value can now contain newlines.
** AC_SUBST_FILE
The substitution now occurs only when @variable@ is on a line by itself,
optionally surrounded by spaces and tabs. The whole line is replaced.
** AC_TYPE_LONG_DOUBLE, AC_TYPE_LONG_DOUBLE_WIDER
New macros to check for long double, and whether it is wider than double.
The old macro AC_C_TYPE_LONG_DOUBLE has been marked as obsolete;
applications should switch to the new macro.
** AC_TYPE_INT8_T, AC_TYPE_INT16_T, AC_TYPE_INT32_T, AC_TYPE_INT64_T,
AC_TYPE_INTMAX_T, AC_TYPE_INTPTR_T, AC_TYPE_LONG_LONG_INT, AC_TYPE_SSIZE_T,
AC_TYPE_UINT8_T, AC_TYPE_UINT16_T, AC_TYPE_UINT32_T, AC_TYPE_UINT64_T,
AC_TYPE_UINTMAX_T, AC_TYPE_UINTPTR_T, AC_TYPE_UNSIGNED_LONG_LONG_INT
New macros to check for C99 and POSIX types.
** AC_USE_SYSTEM_EXTENSIONS
New macro to enable extensions to Posix.
** AH_HEADER
New macro which is defined to the name of the first declared config header
or undefined if no config headers have been declared yet.
** AS_HELP_STRING
The macro correctly handles quadrigraphs now.
** AS_BOURNE_COMPATIBLE, AS_SHELL_SANITIZE, AS_CASE
These macros are new or published now.
** AT_COPYRIGHT
New macro for copyright notices in testsuite files.
** ALLOCA, LIBOBJS, LTLIBOBJS
Object names added to these variables are now prefixed with '${LIBOBJDIR}',
as in '${LIBOBJDIR}alloca.o'. LIBOBJDIR is meant to be defined from
'Makefile.in' in case the object files lie in a different directory.
The LIBOBJDIR feature is experimental.
** autoreconf
Supports --no-recursive now.
** New macros to support Erlang/OTP.
New macros for configuring paths to Erlang tools and libraries:
AC_ERLANG_PATH_ERLC, AC_ERLANG_NEED_ERLC, AC_ERLANG_PATH_ERL,
AC_ERLANG_NEED_ERL, AC_ERLANG_CHECK_LIB, AC_ERLANG_SUBST_ROOT_DIR,
AC_ERLANG_SUBST_LIB_DIR.
New macros for configuring installation of Erlang libraries:
AC_ERLANG_SUBST_INSTALL_LIB_DIR, AC_ERLANG_SUBST_INSTALL_LIB_SUBDIR.
** The manual now mentions Gnulib more prominently.
** New macros to support Objective C.
AC_PROG_OBJC, AC_PROG_OBJCPP.
* Major changes in Autoconf 2.59b
Released 2004-08-20, by Paul Eggert.
** AC_CHECK_ALIGNOF
New macro that computes the default alignment of a type.
** AC_CHECK_TOOL, AC_PATH_TOOL, AC_CHECK_TOOLS
When cross-compiling, these macros will give a warning if the tool
is not prefixed. In the future, unprefixed cross tools will not
be detected; please consult the info documentation for information
about the reason of this change.
** AC_CHECK_TARGET_TOOL, AC_PATH_TARGET_TOOL, AC_CHECK_TARGET_TOOLS
New macros that detect programs whose name is prefixed with the
target type, if the build type and target type are different.
** AC_REQUIRE_AUX_FILE
New trace macro that declares expected auxiliary files.
** AC_PROG_GREP
New macro that tests for a grep program that accepts as a long a line
as possible.
** AC_PROG_EGREP, AC_PROG_FGREP
These macros now require AC_PROG_GREP, and try EGREP="$GREP -E" and
FGREP="$GREP -F" respectively if possible, or else run a path search for
a program that accepts as long a line as possible.
** AC_PROG_SED
New macro that tests for a sed program that truncates as few characters
as possible.
* Major changes in Autoconf 2.59
Released 2003-11-04, by Akim Demaille
** ac_abs_builddir etc.
Absolute file names were actually relative in 2.58.
* Major changes in Autoconf 2.58
Released 2003-11-04, by Akim Demaille
** core.*
core.* files are no longer removed, as they may be valid user files.
** autoreconf and auxiliary directory
Autoreconf creates the auxiliary directory if needed. This is
especially useful for initial "bootstrapping" of fresh CVS checkouts.
** AC_CONFIG_MACRO_DIR
Use this macro to declare the directory for local M4 macros for aclocal.
** AC_LIBOBJS
No longer includes twice the same file in LIBOBJS if invoked
multiple times.
** AC_CONFIG_COMMANDS
The directory for its first argument is automatically created. For
instance, with
AC_CONFIG_COMMANDS([src/modules.hh], [...])
$top_builddir/src/ is created if needed.
** Autotest and local.at
The optional file local.at is always included in Autotest test suites.
** Warnings
The warnings are always issued, including with cached runs.
This became a significant problem since aclocal and automake can
run autoconf behind the scene.
** autoheader warnings
The warnings of autoheader can be turned off, using --warning.
For instance, -Wno-obsolete disables the complaints about acconfig.h
and other deprecated constructs.
** New macros
AC_C_RESTRICT, AC_INCLUDES_DEFAULT, AC_LANG_ASSERT, AC_LANG_WERROR,
AS_SET_CATFILE.
** AC_DECL_SYS_SIGLIST
Works again.
** AC_FUNC_MKTIME
Now checks that mktime is the inverse of localtime.
** Improve DJGPP portability
The Autoconf tools and configure behave better under DJGPP.
** Present But Cannot Be Compiled
New FAQ section dedicated to the mystic
configure: WARNING: pi.h: present but cannot be compiled
configure: WARNING: pi.h: check for missing prerequisite headers?
configure: WARNING: pi.h: proceeding with the preprocessor's result
messages.
** Concurrent executions of autom4te
autom4te now locks its internal files, which enables concurrent
executions of autom4te, likely to happen if automake, autoconf,
autoheader etc. are run simultaneously.
** Libtool
Use of Libtool 1.5 and higher is encouraged. Compatibility with
Libtool pre-1.4 is not checked.
** Autotest
Testsuites no longer rerun failed tests in verbose mode; instead,
failures are logged while the test is run.
In addition, expected failures can be marked as such.
* Major changes in Autoconf 2.57
Released 2002-12-03 by Paul Eggert.
Bug fixes for problems with AIX linker, with freestanding C compilers,
with GNU M4 limitations, and with obsolete copies of GNU documents.
The Free Documentation License has been upgraded from 1.1 to 1.2.
* Major changes in Autoconf 2.56
Released 2002-11-15 by Akim Demaille.
One packaging problem fixed (config/install-sh was not executable).
* Major changes in Autoconf 2.55
Released 2002-11-14 by Akim Demaille.
Release tips:
Have your configure.ac checked by autoscan ("autoscan").
Try the warning options ("autoreconf -fv -Wall").
** Documentation
- AC_CHECK_HEADER, AC_CHECK_HEADERS
More information on proper use.
- Writing Test Programs
This sections explains how to write good test sources to use with
AC_COMPILE_IFELSE etc. It documents AC_LANG_PROGRAM and so forth.
- AC_FOO_IFELSE vs. AC_TRY_FOO
Explains why Autoconf moves from AC_TRY_COMPILE etc. to
AC_COMPILE_IFELSE and AC_LANG_PROGRAM etc.
** autoreconf
- Is more robust to different Gettext installations.
- Produces messages (when --verbose) to be understood by Emacs'
compile mode.
- Supports -W/--warnings.
- -m/--make
Once the GNU Build System reinstalled, run './config.status
--recheck && ./config.status && make' if possible.
** autom4te
- Supports --cache, and --no-cache.
- ~/.autom4te.cfg makes it possible to disable the caching mechanism
(autom4te.cache). See 'Customizing autom4te' in the documentation.
** config.status
Supports --quiet.
** Obsolete options
Support for the obsoleted options -m, --macrodir, -l, --localdir is
dropped in favor of the safer --include/--prepend-include scheme.
** Macros
- New macros
AC_COMPILER_IFELSE, AC_FUNC_MBRTOWC, AC_HEADER_STDBOOL,
AC_LANG_CONFTEST, AC_LANG_SOURCE, AC_LANG_PROGRAM, AC_LANG_CALL,
AC_LANG_FUNC_TRY_LINK, AC_MSG_FAILURE, AC_PREPROC_IFELSE.
- Obsoleted
Obsoleted macros are kept for Autoconf backward compatibility, but
should be avoided in configure.ac. Running autoupdate is advised.
AC_DECL_SYS_SIGLIST.
- AC_DEFINE/AC_DEFINE_UNQUOTED
We have to stop using the old compatibility scheme --that tried to
avoid useless backslashes-- because Libtool 1.4.3 contains a
AC_DEFINE([error_t], [int],
[Define to a type to use for \`error_t' if it is not
otherwise available.])
We have to quote the single quotes and backslashes with \. The old
compatibility scheme saw that ` was backslashed, and therefore did
not quote the single quote... Failure. Hence, Autoconf 2.54 is not
compatible with Libtool. Autoconf 2.55 is, but in some cases might
produce more \ than wanted.
Please, note that in the future the same problem will happen with
AC_MSG_*: use 'autoreconf -f -Wall'.
** Bug Fixes
- Portability of the Autoconf package to Solaris.
- Spurious warnings caused by config.status.
This bug is benign, but painful: on some systems (typically
FreeBSD), warnings such as:
config.status: creating Makefile
mv: Makefile: set owner/group (was: 1357/0): Operation not permitted
could be issued. This is fixed.
- Parallel Builds
Simultaneous executions of config.status are possible again.
- Precious variables accumulation
config.status could stack several copies of the precious variables
assignments.
** Plans for later versions
- ./configure <host>
The compatibility hooks with the old scheme will be completely
removed. Please, advice/use '--build', '--host', and '--target'
only.
- AC_CHECK_HEADER, AC_CHECK_HEADERS
The tests will be stricter, please make sure your invocations are
valid.
- shell functions
Shell functions will gradually be introduced, probably starting with
Autotest. If you know machines which are in use that you suspect
*not* to support shell functions, please run the test suite of
Autoconf 2.55 on it, and report the results to
bug-autoconf@gnu.org.
- AC_MSG_*
Special characters in AC_MSG_* need not be quoted. Currently,
Autoconf has heuristics to decide when a string is escaped, or has
to be escaped. This scheme is fragile, and will be removed; the
only risk is uglified messages. Please, run 'autoreconf -f -Wall'
to find occurrences that will be affected.
* Major changes in Autoconf 2.54
Released 2002-09-13 by Akim Demaille.
** Executables
- autoreconf no longer changes the version of the gettext/po/intl
support files. It now adds the files the correspond to the
AM_GNU_GETTEXT_VERSION declared in configure.ac.
Warning: It now relies on the 'autopoint' program, which is part
of GNU gettext 0.11.4 and newer.
Please note that you need to have a GNU gettext version that
corresponds at least to the AM_GNU_GETTEXT_VERSION declared
in configure.ac. You can upgrade to newer GNU gettext versions,
though, without needing to change configure.ac.
- The -I DIR or --include=DIR option now appends DIR to the include path
instead of prepending; this is for consistency with other GNU tools.
The new -B DIR or --prepend-include=DIR option has the old behavior.
** Macros
- AC_OUTPUT
Now handles all the gory details about LIBOBJS and LTLIBOBJS.
Please, remove lines such as
# This is necessary so that .o files in LIBOBJS are also
# built via the ANSI2KNR-filtering rules.
LIBOBJS=`echo $LIBOBJS|sed 's/\.o /\$U.o /g;s/\.o$/\$U.o/'`
and read the 'AC_LIBOBJ vs LIBOBJS' section. Do not define U in
your Makefiles either.
- AC_CONFIG_LINKS now makes copies if it can't make links.
- AC_FUNC_FNMATCH now tests only for POSIX compatibility, reverting to
Autoconf 2.13 behavior. The new macro AC_FUNC_FNMATCH_GNU also
tests for GNU extensions to fnmatch, and replaces fnmatch if needed.
- AC_FUNC_SETVBUF_REVERSED no longer fails when cross-compiling.
- AC_PROG_CC_STDC is integrated into AC_PROG_CC.
- AC_PROG_F77 default search no longer includes cf77 and cfg77.
- New macros
AC_C_BACKSLASH_A, AC_CONFIG_LIBOBJ_DIR, AC_GNU_SOURCE,
AC_PROG_EGREP, AC_PROG_FGREP, AC_REPLACE_FNMATCH,
AC_FUNC_FNMATCH_GNU, AC_FUNC_REALLOC, AC_TYPE_MBSTATE_T.
- AC_FUNC_GETLOADAVG
looks for getloadavg.c in the CONFIG_LIBOBJ_DIR.
- AC_FUNC_MALLOC
Now defines HAVE_MALLOC to 0 if 'malloc' does not work, and asks
for an AC_LIBOBJ replacement.
** Bug fixes
- Spurious complaints from 'm4_bmatch' about invalid regular
expressions are suppressed.
- Empty top_builddirs are properly handled.
- AC_CHECK_MEMBER works correctly when the member is an aggregate.
- AC_PATH_PROG
Now colon in the optional path arguments are properly handled.
** Improved portability
- Both Autoconf the package, and the scripts it produces, should run
more reliably with Zsh. Bear in mind it is the default Bourne shell
on Darwin.
- Autoconf and the scripts it produces no longer assume the existence of
the obsolescent commands egrep and fgrep.
** Documentation
- Limitations of Make
More of them.
- GNATS
The GNATS base moved to
https://bugs.gnu.org/cgi-bin/gnatsweb.pl?database=autoconf
(It is no longer available, though.)
** Misc.
- config.log
Now contains the list of output variables and files (AC_SUBST,
AC_SUBST_FILES).
* Major changes in Autoconf 2.53
Released 2002-03-08 by Akim Demaille.
** Requirements
Perl 5.005_03 or later is required: autom4te is written in Perl and is
needed by autoconf. autoheader, autoreconf, ifnames, and autoscan are
rewritten in Perl.
** Documentation
- AC_INIT
Argument requirements, output variables, defined macros.
- M4sugar, M4sh, Autotest
First sketch.
- Double quoting macros
AC_TRY_CPP, AC_TRY_COMPILE, AC_TRY_LINK and AC_TRY_RUN.
- Licensing
The Autoconf manual is now distributed under the terms of the GNU FDL.
- Section 'Hosts and Cross-Compilation'
Explains the rationale for the 2.5x changes in the cross-compilation
chain, and in the relationships between build, host, and target
types.
Emphasizes that 'cross-compilation' == '--host is given'.
If you are working on compilers etc., be sure to read this section.
- Section 'AC_LIBOBJ vs. LIBOBJS'
Explains why assigning LIBOBJS directly is now an error.
Details how to update the code.
** configure
- $LINENO
Now used instead of hard coded line numbers.
This eases the comparison of 'configure's, and diminishes the
pressure over control version archives.
Automatic replacement for shells that don't support this feature.
- New output variables
@builddir@, @top_builddir@, @abs_srcdir@, @abs_top_srcdir@, @abs_builddir@,
@abs_top_builddir@.
** Emacs
Autoconf and Autotest modes are provided.
** Executables
- autom4te
New, used by the Autoconf suite to cache and speed up most processing.
- --force, -f
Supported by autom4te, autoconf and autoheader.
- --include, -I
Replaces --autoconf-dir and --localdir in autoconf, autoheader,
autoupdate, and autoreconf.
- autoreconf
No longer passes --cygnus, --foreign, --gnits, --gnu, --include-deps:
automake options are to be given via AUTOMAKE_OPTIONS.
- autoreconf
Runs gettextize and libtoolize when appropriate.
- autoreconf
--m4dir is no longer supported.
- autoreconf
Now runs only in the specified directories, defaulting to '.',
but understands AC_CONFIG_SUBDIRS for dependent directories.
Before, it used to run on all the 'configure.ac' found in the
current tree.
Independent packages are properly updated.
** Bug fixes
- The top level $prefix is propagated to the AC_CONFIG_SUBDIRS configures.
- AC_TRY_RUN
Under the user pressure, $? is finally available. Probably a mistake.
- AC_F77_LIBRARY_LDFLAGS now supports the HP/UX f90 compiler.
- Precious variables accumulation
config.status could stack several copies of the precious variables
assignments.
- AC_PATH_PROG and family.
Works properly when given a literal path.
- AC_FUNC_SETPGRP
Somewhere since 2.13, the result had been reversed.
** C Macros
- AC_C_BIGENDIAN supports the cross-compiling case.
- AC_C_BIGENDIAN accepts ACTION-IF-TRUE, ACTION-IF-FALSE, and
ACTION-IF-UNKNOWN arguments. All are optional, and the default
for ACTION-IF-TRUE is to define WORDS_BIGENDIAN like AC_C_BIGENDIAN
always did.
- AC_C_LONG_DOUBLE now succeeds only if 'long double' has more range or
precision than 'double'.
** Generic macros
- AC_INIT
It now defines the preprocessor symbols PACKAGE_NAME,
PACKAGE_TARNAME, PACKAGE_VERSION, PACKAGE_STRING, and
PACKAGE_BUGREPORT.
- AC_INIT
Admits a fourth optional parameter: the tar name.
- AC_CONFIG_COMMANDS, HEADERS, FILES, LINKS.
Provide the user with srcdir, ac_srcdir, ac_top_srcdir, ac_builddir,
ac_top_builddir, ac_abs_srcdir, ac_abs_top_srcdir, ac_abs_builddir,
ac_abs_top_builddir.
- AC_CONFIG_COMMANDS, HEADERS, FILES, LINKS and AC_OUTPUT.
Are much less expensive when using long lists of files.
- AC_PREFIX_PROGRAM
Works with shell variables, and non alphanumeric names.
** Library macros
- AC_FUNC_STRERROR_R now sets STRERROR_R_CHAR_P, not HAVE_WORKING_STRERROR_R,
because POSIX 1003.1-200x draft 7 says strerror_r returns int, not char *.
- AC_FUNC_STRTOD substitutes POW_LIB.
- AC_FUNC_STRNLEN
New.
* Major changes in Autoconf 2.52
Released 2001-07-18 by Akim Demaille.
** Documentation
- AC_ARG_VAR
- Quadrigraphs
This feature was present in autoconf 2.50 but was not documented.
For example, '@<:@' is translated to '[' just before output. This
is useful when writing strings that contain unbalanced quotes, or
other hard-to-quote constructs.
- m4_pattern_forbid, m4_pattern_allow
- Tips for upgrading from 2.13.
- Using autoscan to maintain a configure.ac.
** Default includes
- Now include stdint.h.
- sys/types.h and sys/stat.h are guarded.
- strings.h is included if available, and not conflicting with string.h.
** Bug fixes
- The test suite is more robust and presents less false failures.
- Invocation of GNU M4 now robust to POSIXLY_CORRECT.
- configure accepts --prefix='' again.
- AC_CHECK_LIB works properly when its first argument is not a
literal.
- HAVE_INTTYPES_H is defined only if not conflicting with sys/types.h.
- build_, host_, and target_alias are AC_SUBST as in 2.13.
- AC_ARG_VAR properly propagates precious variables inherited from the
environment to ./config.status.
- Using --program-suffix/--program-prefix is portable.
- Failures to detect the default compiler's output extension are less
likely.
- 'config.status foo' works properly when 'foo' depends on variables
set in an AC_CONFIG_THING INIT-CMD.
- autoheader is more robust to broken input.
- Fixed Fortran name-mangling and link tests on a number of systems,
e.g. NetBSD; see AC_F77_DUMMY_MAIN, below.
** Generic macros
- AC_CHECK_HEADER and AC_CHECK_HEADERS support a fourth argument to
specify pre-includes. In this case, the headers are compiled with
cc, not merely preprocessed by cpp. Therefore it is the _usability_
of a header which is checked for, not just its availability.
- AC_ARG_VAR refuses to run configure when precious variables have
changed.
- Versions of compilers are dumped in the logs.
- AC_CHECK_TYPE recognizes use of 'foo_t' as a replacement type.
** Specific Macros
- AC_PATH_XTRA only adds -ldnet to $LIBS if it's needed to link.
- AC_FUNC_WAIT3 and AC_SYS_RESTARTABLE_SYSCALLS are obsoleted.
- AM_FUNC_ERROR_AT_LINE, AM_FUNC_FNMATCH, AM_FUNC_MKTIME,
AM_FUNC_OBSTACK, and AM_FUNC_STRTOD are now activated.
Be sure to read 'Upgrading from Version 2.13' to understand why
running 'autoupdate' is needed.
- AC_F77_DUMMY_MAIN, AC_F77_MAIN: new macros to detect whether
a main-like routine is required/possible when linking C/C++ with
Fortran. Users of e.g. AC_F77_WRAPPERS should be aware of these.
- AC_FUNC_GETPGRP behaves better when cross-compiling.
* Major changes in Autoconf 2.51
There was no release of Autoconf 2.51 since some packagers had used
this version number without permission to ship intermediary versions
of 2.50. The version was skipped to avoid confusion.
* Major changes in Autoconf 2.50
Released 2001-05-21 by Akim Demaille.
** Lots of bug fixes
There have been far too many to enumerate them here. Check out
ChangeLog if you really want to know more.
** Improved documentation
In particular, portability issues are better covered.
** Use of Automake
All the standard GNU Makefile targets are supported. The layout has
changed: m4/ holds the M4 extensions Autoconf needs for its
configuration, doc/ contains the documentation, and tests/ contains
the test suite.
** Man pages are provided
For autoconf, autoreconf, autoupdate, autoheader, autoscan, ifnames,
config.guess, config.sub.
** autoconf
- --trace
Provides a safe and powerful means to trace the macro uses. This
provide the parsing layer for tools which need to 'study'
configure.in.
- --warnings
Specify what category of warnings should be enabled.
- When recursing into subdirectories, try for configure.gnu before
configure to adapt for packages not using autoconf on case-insensitive
file systems.
- Diagnostics
More errors are now caught (circular AC_REQUIRE dependencies,
AC_DEFINE in the action part of an AC_CACHE_CHECK, too many pops
etc.). In addition, their location and call stack are given.
** autoupdate
autoupdate is much more powerful, and is able to provide the glue code
which might be needed to move from an old macro to its newer
equivalent.
You are strongly encouraged to use it to modernize both your
'configure.in' and your .m4 extension files.
** autoheader
The internal machinery of autoheader has completely changed. As a
result, using 'acconfig.h' should be considered to be obsoleted, and
you are encouraged to get rid of it using the AH macros.
** autoreconf
Extensive overhaul.
** Fortran 77 compilers
Globally, the support for Fortran 77 is considerably improved.
Support for automatically determining a Fortran 77 compiler's
name-mangling scheme. New CPP macros F77_FUNC and F77_FUNC_ are
provided to wrap C/C++ identifiers, thus making it easier and more
transparent for C/C++ to call Fortran 77 routines, and Fortran 77 to
call C/C++ routines. See the Texinfo documentation for details.
** Test suite
The test suite no longer uses DejaGNU. It should be easy to submit
test cases in this new framework.
** configure
- --help, --help=long, -hl
no longer dumps useless items.
- --help=short, -hs
lists only specific options.
- --help=recursive, -hr
displays the help of all the embedded packages.
- Remembers environment variables when reconfiguring.
The previous scheme to set envvar before running configure was
ENV=VAL ./configure
what prevented configure from remembering the environment in which
it was run, therefore --recheck was run in an inconsistent
environment. Now, one should run
./configure ENV=VAR
and then --recheck will work properly. Variables declared with
AC_ARG_VAR are also preserved.
- cross-compilation
$build defaults to `config.guess`, $host to $build, and then $target
to $host.
Cross-compilation is a global status of the package, it no longer
depends upon the current language.
Cross compilation is enabled iff the user specified '--host'.
'configure' now fails if it can't run the executables it compiles,
unless cross-compilation is enabled.
- Cache file
The cache file is disabled by default. The new options
'--config-cache', '-C' set the cache to 'config.cache'.
** config.status
- faster
Much faster on most architectures.
- concurrent executions
It is safe to use 'make -j' with config.status.
- human interface improved
It is possible to invoke
./config.status foobar
instead of the former form (still valid)
CONFIG_COMMANDS= CONFIG_HEADERS= CONFIG_LINKS= \
CONFIG_FILES=foobar:foo.in:bar.in \
./config.status
The same holds for configuration headers and links.
You can instantiate unknown files and headers:
./config.status --header foo.h:foo.h.in --file bar:baz
- has a useful --help
- accepts special file name "-" for stdin/stdout
** Identity Macros
- AC_COPYRIGHT
Specify additional copyright information.
- AC_INIT
Now expects the identity of the package as argument.
** General changes.
- Uniform quotation
Most macros, if not all, now strictly follow the 'one quotation
level' rule. This results in a more predictable expansion.
- AC_REQUIRE
A sly bug in the AC_REQUIRE machinery, which could produce incorrect
configure scripts, was fixed by Axel Thimm.
** Setup Macros
- AC_ARG_VAR
Document and ask for the registration of an envvar.
- AC_CONFIG_SRCDIR
Specifies the file which 'configure' should look for when trying to
find the source tree (used to be handled by AC_INIT).
- AC_CONFIG_COMMANDS
To add new actions to config.status. Should be used instead of
AC_OUTPUT_COMMANDS.
- AC_CONFIG_LINKS
Replaces AC_LINK_FILES.
- AC_CONFIG_HEADERS, AC_CONFIG_COMMANDS, AC_CONFIG_SUBDIRS,
AC_CONFIG_LINKS, and AC_CONFIG_FILES
They now obey sh: you should no longer use shell variables as
argument. Instead of
test "$package_foo_enabled" = yes && $my_subdirs="$my_subdirs foo"
AC_CONFIG_SUBDIRS($my_subdirs)
write
if test "$package_foo_enabled" = yes; then
AC_CONFIG_SUBDIRS(foo)
fi
- AC_HELP_STRING
To format an Autoconf macro's help string so that it looks pretty
when the user executes 'configure --help'.
** Generic Test Macros
- AC_CHECK families
The interface of the AC_CHECK families of macros (decl, header,
type, member, func) is now uniform. They support the same set of
default includes.
- AC_CHECK_DECL, AC_CHECK_DECLS
To check whether a symbol is declared.
- AC_CHECK_SIZEOF, AC_C_CHAR_UNSIGNED.
No longer need a cross-compilation default.
- AC_CHECK_TYPE
The test it performs is much more robust than previously, and makes
it possible to test builtin types in addition to typedefs.
It is now schizophrenic:
- AC_CHECK_TYPE(TYPE, REPLACEMENT)
remains for backward compatibility, but its use is discouraged.
- AC_CHECK_TYPE(TYPE, IF-FOUND, IF-NOT-FOUND, INCLUDES)
behaves exactly like the other AC_CHECK macros.
- AC_CHECK_TYPES
Checks whether given types are supported by the system.
- AC_CHECK_MEMBER, AC_CHECK_MEMBERS
Check for given members in aggregates (e.g., pw_gecos in struct
passwd).
- AC_PROG_CC_STDC
Checks if the compiler supports ISO C, included when needs special
options.
- AC_PROG_CPP
Checking whether the preprocessor indicates missing includes by the
error code. stderr is checked by AC_TRY_CPP only as a fallback.
- AC_LANG
Takes a language as argument and replaces AC_LANG_C,
AC_LANG_CPLUSPLUS and AC_LANG_FORTRAN77.
- AC_LANG_PUSH, AC_LANG_POP
Are preferred to AC_LANG_SAVE, AC_LANG_RESTORE.
** Specific Macros
- AC_FUNC_CHOWN, AC_FUNC_MALLOC, AC_FUNC_STRERROR_R,
AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK, AC_FUNC_STAT, AC_FUNC_LSTAT,
AC_FUNC_ERROR_AT_LINE, AC_FUNC_OBSTACK, AC_FUNC_STRTOD, AC_FUNC_FSEEKO.
New.
- AC_FUNC_GETGROUPS
Sets GETGROUPS_LIBS.
- AC_FUNC_GETLOADAVG
Defines 'HAVE_STRUCT_NLIST_N_UN_N_NAME' instead of 'NLIST_NAME_UNION'.
- AC_PROG_LEX
Now integrates 'AC_DECL_YYTEXT' which is obsoleted.
- AC_SYS_LARGEFILE
Arrange for large-file support.
- AC_EXEEXT, AC_OBJEXT
You are no longer expected to use them: their computation is
performed by default.
** C++ compatibility
Every macro has been revisited in order to support at best CC=c++.
Major changes in Autoconf 2.14:
There was no release of GNU Autoconf 2.14.
Major changes in Autoconf 2.13:
Released 1999-05-01 by Ben Elliston.
* Support for building on 32-bit Windows systems where the only available C or
C++ compiler is the Microsoft Visual C++ command line compiler
('cl'). Additional support for building on 32-bit Windows systems which are
using the Cygwin or Mingw32 environments.
* Support for alternative object file and executable file extensions.
On 32-bit Windows, for example, these are .obj and .exe. These are discovered
using AC_OBJEXT and AC_EXEEXT, which substitute @OBJEXT@ and
@EXEEXT@ in the output, respectively.
* New macros: AC_CACHE_LOAD, AC_CACHE_SAVE, AC_FUNC_SELECT_ARGTYPES,
AC_VALIDATE_CACHED_SYSTEM_TUPLE, AC_SEARCH_LIBS, AC_TRY_LINK_FUNC,
AC_C_STRINGIZE, AC_CHECK_FILE(S), AC_PROG_F77 (and friends).
* AC_DEFINE now has an optional third argument for a description to be
placed in the config header input file (e.g. config.h.in).
* The C++ code fragment compiled for the C++ compiler test had to be
improved to include an explicit return type for main(). This was
causing failures on systems using recent versions of the EGCS C++
compiler.
* Fixed an important bug in AC_CHECK_TYPE that would cause a configure
script to report that 'sometype_t' was present when only 'type_t'
was defined.
* Merge of the FSF version of config.guess and config.sub to modernize
these scripts. Add support for a few new hosts in config.guess.
Incorporate latest versions of install-sh, mkinstalldirs and
texinfo.tex from the FSF.
* autoreconf is capable of running automake if necessary (and
applicable).
* Support for Fortran 77. See the Texinfo documentation for details.
* Bug fixes and workarounds for quirky bugs in vendor utilities.
Major changes in Autoconf 2.12:
Released 1996-11-26 by David J. MacKenzie
* AC_OUTPUT and AC_CONFIG_HEADERS can create output files by
concatenating multiple input files separated by colons, like so:
AC_CONFIG_HEADERS([config.h:conf.pre:config.h.in:conf.post])
AC_OUTPUT([Makefile:Makefile.in:Makefile.rules])
The arguments may be shell variables, to compute the lists on the fly.
* AC_LINK_FILES and AC_CONFIG_SUBDIRS may be called multiple times.
* New macro AC_OUTPUT_COMMANDS adds more commands to run in config.status.
* Bug fixes.
Major changes in Autoconf 2.11:
Released November 18th, 1996, by David J. MacKenzie
* AC_PROG_CC and AC_PROG_CXX check whether the compiler works.
They also default CFLAGS/CXXFLAGS to "-g -O2" for gcc, instead of "-g -O".
* AC_REPLACE_FUNCS defines HAVE_foo if the system has the function 'foo'.
* AC_CONFIG_HEADERS expands shell variables in its argument.
* New macros: AC_FUNC_FNMATCH, AC_FUNC_SETPGRP.
* The "checking..." messages and the source code for test programs that
fail are saved in config.log.
* Another workaround has been added for seds with small command length limits.
* config.sub and config.guess recognize more system types.
* Bug fixes.
Major changes in Autoconf 2.10:
Released May 7th, 1996, by Roland McGrath
* Bug fixes.
* The cache variable names used by 'AC_CHECK_LIB(LIB, FUNC, ...)' has
changed: now $ac_cv_lib_LIB_FUNC, previously $ac_cv_lib_LIB.
Major changes in Autoconf 2.9:
Released March 16th, 1996, by Roland McGrath
* Bug fixes.
Major changes in Autoconf 2.8:
Released March 8th, 1996, by Roland McGrath
* Bug fixes.
Major changes in Autoconf 2.7:
Released November 22nd, 1995, by David J. MacKenzie
* Bug fixes.
Major changes in Autoconf 2.6:
Released November 20th, 1995, by David J. MacKenzie
* Bug fixes.
Major changes in Autoconf 2.5:
Released November 17th, 1995, by Roland McGrath
* New configure options --bindir, --libdir, --datadir, etc., with
corresponding output variables.
* New macro: AC_CACHE_CHECK, to make using the cache easier.
* config.log contains the command being run as well as any output from it.
* AC_CHECK_LIB can check for libraries with "." or "/" or "+" in their name.
* AC_PROG_INSTALL doesn't cache a name for install-sh, for sharing caches.
* AC_CHECK_PROG, AC_PATH_PROG, AC_CHECK_PROGS, AC_PATH_PROGS, and
AC_CHECK_TOOL can search a path other than $PATH.
* AC_CHECK_SIZEOF takes an optional size to use when cross-compiling.
Major changes in Autoconf 2.4:
Released June 14th, 1995, by David J. MacKenzie
* Fix a few bugs found by Emacs testers.
Major changes in Autoconf 2.3:
Released March 27th, 1995, by David J. MacKenzie
* Fix the cleanup trap in several ways.
* Handle C compilers that are picky about option placement.
* ifnames gets the version number from the right directory.
Major changes in Autoconf 2.2:
Released March 8th, 1995, by David J. MacKenzie
* The ifnames utility is much faster but requires a "new awk" interpreter.
* AC_CHECK_LIB and AC_HAVE_LIBRARY check and add the new
library before existing libs, not after, in case it uses them.
* New macros: AC_FUNC_GETPGRP, AC_CHECK_TOOL.
* Lots of bug fixes.
* Many additions to the TODO file :-)
Major changes in Autoconf 2.1:
Released November 4th, 1994, by David J. MacKenzie
* Fix C++ problems.
* More explanations in the manual.
* Fix a spurious failure in the testsuite.
* Clarify some warning messages.
* autoreconf by default only rebuilds configure and config.h.in files
that are older than any of their particular input files; there is a
--force option to use after installing a new version of Autoconf.
Thanks to everybody who's submitted changes and additions to Autoconf!
I've incorporated many of them, and am still considering others for
future releases -- but I didn't want to postpone this release indefinitely.
Caution: don't indiscriminately rebuild configure scripts with
Autoconf version 2. Some configure.in files need minor adjustments to
work with it; the documentation has a chapter on upgrading. A few
configure.in files, including those for GNU Emacs and the GNU C
Library, need major changes because they relied on undocumented
internals of version 1. Future releases of those packages will have
updated configure.in files.
It's best to use GNU M4 1.3 (or later) with Autoconf version 2.
Autoconf now makes heavy use of M4 diversions, which were implemented
inefficiently in GNU M4 releases before 1.3.
Major changes in Autoconf 2.0:
Released October 26th, 1994, by David J. MacKenzie
** New copyright terms:
* There are no restrictions on distribution or use of configure scripts.
** Documentation:
* Autoconf manual is reorganized to make information easier to find
and has several new indexes.
* INSTALL is reorganized and clearer and is now made from Texinfo source.
** New utilities:
* autoscan to generate a preliminary configure.in for a package by
scanning its source code for commonly used nonportable functions,
programs, and header files.
* ifnames to list the symbols used in #if and #ifdef directives in a
source tree.
* autoupdate to update a configure.in to use the version 2 macro names.
* autoreconf to recursively remake configure and configuration header
files in a source tree.
** Changed utilities:
* autoheader can take pieces of acconfig.h to replace config.h.{top,bot}.
* autoconf and autoheader can look for package-local definition files
in an alternate directory.
** New macros:
* AC_CACHE_VAL to share results of tests between configure runs.
* AC_DEFUN to define macros, automatically AC_PROVIDE them, and ensure
that macros invoked with AC_REQUIRE don't interrupt other macros.
* AC_CONFIG_AUX_DIR, AC_CANONICAL_SYSTEM, AC_CANONICAL_HOST, AC_LINK_FILES to
support deciding unguessable features based on the host and target types.
* AC_CONFIG_SUBDIRS to recursively configure a source tree.
* AC_ARG_PROGRAM to use the options --program-prefix,
--program-suffix, and --program-transform-name to change the names
of programs being installed.
* AC_PREFIX_DEFAULT to change the default installation prefix.
* AC_TRY_COMPILE to compile a test program without linking it.
* AC_CHECK_TYPE to check whether sys/types.h or stdlib.h defines a given type.
* AC_CHECK_LIB to check for a particular function and library.
* AC_MSG_CHECKING and AC_MSG_RESULT to print test results, on a single line,
whether or not the test succeeds. They obsolete AC_CHECKING and AC_VERBOSE.
* AC_SUBST_FILE to insert one file into another.
* AC_FUNC_MEMCMP to check whether memcmp is 8-bit clean.
* AC_FUNC_STRFTIME to find strftime even if it's in -lintl.
* AC_FUNC_GETMNTENT to find getmntent even if it's in -lsun or -lseq.
* AC_HEADER_SYS_WAIT to check whether sys/wait.h is POSIX.1 compatible.
** Changed macros:
* Many macros renamed systematically, but old names are accepted for
backward compatibility.
* AC_OUTPUT adds the "automatically generated" comment to
non-Makefiles where it finds @configure_input@ in an input file, to
support files with various comment syntaxes.
* AC_OUTPUT does not replace "prefix" and "exec_prefix" in generated
files when they are not enclosed in @ signs.
* AC_OUTPUT allows the optional environment variable CONFIG_STATUS to
override the file name "config.status".
* AC_OUTPUT takes an optional argument for passing variables from
configure to config.status.
* AC_OUTPUT and AC_CONFIG_HEADERS allow you to override the input-file names.
* AC_OUTPUT automatically substitutes the values of CFLAGS, CXXFLAGS,
CPPFLAGS, and LDFLAGS from the environment.
* AC_PROG_CC and AC_PROG_CXX now set CFLAGS and CXXFLAGS, respectively.
* AC_PROG_INSTALL looks for install-sh or install.sh in the directory
specified by AC_CONFIG_AUXDIR, or srcdir or srcdir/.. or
srcdir/../.. by default.
* AC_DEFINE, AC_DEFINE_UNQUOTED, and AC_SUBST are more robust and smaller.
* AC_DEFINE no longer prints anything, because of the new result reporting
mechanism (AC_MSG_CHECKING and AC_MSG_RESULT).
* AC_VERBOSE pays attention to --quiet/--silent, not --verbose.
* AC_ARG_ENABLE and AC_ARG_WITH support whitespace in the arguments to
--enable- and --with- options.
* AC_CHECK_FUNCS and AC_CHECK_HEADERS take optional shell commands to
execute on success or failure.
* Checking for C functions in C++ works.
** Removed macros:
* AC_REMOTE_TAPE and AC_RSH removed; too specific to tar and cpio, and
better maintained with them.
* AC_ARG_ARRAY removed because no one was likely using it.
* AC_HAVE_POUNDBANG replaced with AC_SYS_INTERPRETER, which doesn't
take arguments, for consistency with all of the other specific checks.
** New files:
* Comes with config.sub and config.guess, and uses them optionally.
* Uses config.cache to cache test results. An alternate cache file
can be selected with the --cache-file=FILE option.
* Uses optional shell scripts $prefix/share/config.site and
$prefix/etc/config.site to perform site or system specific initializations.
* configure saves compiler output to ./config.log for debugging.
* New files autoconf.m4 and autoheader.m4 load the other Autoconf macros.
* acsite.m4 is the new name for the system-wide aclocal.m4.
* Has a DejaGnu test suite.
Major changes in Autoconf 1.11:
* AC_PROG_INSTALL calls install.sh with the -c option.
* AC_SET_MAKE cleans up after itself.
* AC_OUTPUT sets prefix and exec_prefix if they weren't set already.
* AC_OUTPUT prevents shells from looking in PATH for config.status.
Plus a few other bug fixes.
Major changes in Autoconf 1.10:
* autoheader uses config.h.bot if present, analogous to config.h.top.
* AC_PROG_INSTALL looks for install.sh in srcdir or srcdir/.. and
never uses cp.
* AC_PROG_CXX looks for cxx as a C++ compiler.
Plus several bugs fixed.
Major changes in Autoconf 1.9:
* AC_YYTEXT_POINTER replaces AC_DECLARE_YYTEXT.
* AC_SIZEOF_TYPE generates the cpp symbol name automatically,
and autoheader generates entries for those names automatically.
* AC_FIND_X gets the result from xmkmf correctly.
* AC_FIND_X assumes no X if --without-x was given.
* AC_FIND_XTRA adds libraries to the variable X_EXTRA_LIBS.
* AC_PROG_INSTALL finds OSF/1 installbsd.
Major changes in Autoconf 1.8:
** New macros:
* New macros AC_LANG_C, AC_LANG_CPLUSPLUS, AC_LANG_SAVE, AC_LANG_RESTORE,
AC_PROG_CXX, AC_PROG_CXXCPP, AC_REQUIRE_CPP
for checking both C++ and C features in one configure script.
* New macros AC_CHECKING, AC_VERBOSE, AC_WARN, AC_ERROR for printing messages.
* New macros AC_FIND_XTRA, AC_MMAP, AC_SIZEOF_TYPE, AC_PREREQ,
AC_SET_MAKE, AC_ENABLE.
** Changed macros:
* AC_FIND_X looks for X in more places.
* AC_PROG_INSTALL defaults to install.sh instead of cp, if it's in srcdir.
install.sh is distributed with Autoconf.
* AC_DECLARE_YYTEXT has been removed because it can't work, pending
a rewrite of quoting in AC_DEFINE.
* AC_OUTPUT adds its comments in C format when substituting in C files.
* AC_COMPILE_CHECK protects its ECHO-TEXT argument with double quotes.
** New or changed command line options:
* configure accepts --enable-FEATURE[=ARG] and --disable-FEATURE options.
* configure accepts --without-PACKAGE, which sets withval=no.
* configure accepts --x-includes=DIR and --x-libraries=DIR.
* Giving --with-PACKAGE no argument sets withval=yes instead of withval=1.
* configure accepts --help, --version, --silent/--quiet, --no-create options.
* configure accepts and ignores most other Cygnus configure options, and
warns about unknown options.
* config.status accepts --help, --version options.
** File names and other changes:
* Relative srcdir values are not made absolute.
* The values of @prefix@ and @exec_prefix@ and @top_srcdir@ get substituted.
* Autoconf library files are installed in ${datadir}/autoconf, not ${datadir}.
* autoheader optionally copies config.h.top to the beginning of config.h.in.
* The example Makefile dependencies for configure et al. work better.
* Namespace cleanup: all shell variables used internally by Autoconf
have names beginning with 'ac_'.
More big improvements are in process for future releases, but have not
yet been (variously) finished, integrated, tested, or documented enough
to release yet.
Major changes in Autoconf 1.7:
* New macro AC_OBSOLETE.
* Bugs in Makefile.in fixed.
* AC_LONG_FILE_NAMES improved.
Major changes in Autoconf 1.6:
* New macro AC_LONG_64_BITS.
* Multiple .h files can be created.
* AC_FIND_X looks for X files directly if it doesn't find xmkmf.
* AC_ALLOCA defines C_ALLOCA if using alloca.c.
* --with-NAME can take a value, e.g., --with-targets=sun4,hp300bsd.
* Unused --no-create option to configure removed.
* autoheader doesn't change the timestamp of its output file if
the file didn't change.
* All macros that look for libraries now use AC_HAVE_LIBRARY.
* config.status checks three optional environment variables to
modify its behavior.
* The usual bug fixes.
Major changes in Autoconf 1.5:
* New macros AC_FIND_X, AC_OFF_T, AC_STAT_MACROS_BROKEN, AC_REVISION.
* autoconf and autoheader scripts have GNU standards conforming
--version and --help options (they print their message and exit).
* Many bug fixes.
Major changes in Autoconf 1.4:
* New macros AC_HAVE_POUNDBANG, AC_TIME_WITH_SYS_TIME, AC_LONG_DOUBLE,
AC_GETGROUPS_T, AC_DEFINE_UNQUOTED.
* autoconf and autoheader use the M4 environment variable to determine the
name of the M4 program to use.
* The --macrodir option to autoconf and autoheader specifies the directory
in which acspecific.m4, acgeneral.m4, etc. reside if not the default.
* autoconf and autoheader can take '-' as their file names, which means to
read stdin as input.
* Resulting configure scripts can take a --verbose option which causes them
to print the results of their tests.
* AC_DEFINE quotes its second argument in such a way that spaces, magic
shell characters, etc. will be preserved during various stages of
expansion done by the shell. If you don't want this, use
AC_DEFINE_UNQUOTED instead.
* Much textual processing done with external calls to tr and sed have been
internalized with builtin M4 'patsubst' and 'translit' calls.
* AC_OUTPUT doesn't hardwire the file names it outputs. Instead, you can
set the shell variables 'gen_files' and 'gen_config' to the list of
file names to output.
* AC_DECLARE_YYTEXT does an AC_SUBST of 'LEX_OUTPUT_ROOT', which may be
"lex.yy" or "lexyy", depending on the system.
* AC_PROGRAMS_CHECK takes an optional third arg. If given, it is used as
the default value.
* If AC_ALLOCA chooses alloca.c, it also defines STACK_DIRECTION.
* AC_CONST works much more reliably on more systems.
* Many bug fixes.
Major changes in Autoconf 1.3:
configure no longer requires awk for packages that use a config.h.
Support handling --with-PACKAGE options.
New 'autoheader' script to create 'config.h.in' from 'configure.in'.
Ignore troublesome -lucb and -lPW when searching for alloca.
Rename --exec_prefix to --exec-prefix for GNU standards conformance.
Improve detection of STDC library.
Add AC_HAVE_LIBRARY to check for non-default libraries.
Function checking should work with future GNU libc releases.
Major changes in Autoconf 1.2:
The --srcdir option is now usually unnecessary.
Add a file containing sample comments describing CPP macros.
A comment in config.status tells which host it was configured on.
Substituted variable values can now contain commas.
Fix bugs in various feature checks.
Major changes in Autoconf 1.1:
Added AC_STRCOLL macro.
Made AC_GETLOADAVG check for more things.
AC_OUTPUT argument is now optional.
Various bug fixes.
-----
Copyright (C) 1993-1996, 1998-2017, 2020-2023 Free Software Foundation,
Inc.
Copying and distribution of this file, with or without modification,
are permitted in any medium without royalty provided the copyright
notice and this notice are preserved. This file is offered as-is,
without warranty of any kind.
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