In documentation and comments, prefer the more-common “C89” to the
equivalent “C90”, and use 2-digit years for C standards as that’s
common usage. Remove some confusing old doc for pre-C89 systems,
as Autoconf assumes C89 or later. Mention C17 and C23 briefly.
Improve doc for malloc, realloc.
This fixes all of the remaining failures exposed by running the
testsuite with GCC 12 and
CC='cc -Wimplicit-function-declaration -Wold-style-definition
-Wimplicit-int -Werror'
.
* lib/autoconf/c.m4 (_AC_C_C89_TEST_GLOBALS): Don’t use K&R function
definitions.
* lib/autoconf/specific.m4 (AC_SYS_RESTARTABLE_SYSCALLS): Likewise.
(AC_FUNC_MKTIME): Declare functions taking no arguments as ‘fn (void)’
not ‘fn ()’.
* lib/autoconf/c.m4 (_AC_C_C99_TEST_GLOBALS): Declare free().
* lib/autoconf/programs.m4 (AC_PROG_MKDIR_P):
Fall back on mkdir -p instead of on a relative path to
install-sh, as the latter now seems to be more of a problem
than the former.
Problem and solution reported by Roger Crew in:
https://lists.gnu.org/r/bug-autoconf/2022-09/msg00005.html
* lib/m4sugar/m4sh.m4 (_m4_divert(BINSH)): Change from 0 to 1,
and add 2 to HEADER-REVISION, HEADER-COMMENT, HEADER-COPYRIGHT,
M4SH-SANITIZE, M4SH-INIT-FN, and M4SH-INIT.
Copyright-paperwork-exempt: yes
Notced unstable key order when debugging unrelated bug.
Data::Dumper's SortKeys() makes ordering stable and decreases
diffs from run to run. No functional change otherwise.
* lib/Autom4te/C4che.pm
* lib/Autom4te/Request.pm: Sort request keys in serialization.
Copyright-paperwork-exempt: yes
* lib/autoconf/c.m4 (AC_LANG_CALL, AC_LANG_FUNC_LINK_TRY):
Use '(void)' rather than '()' in function prototypes, as the latter
provokes fatal errors in some compilers nowadays.
* lib/autoconf/functions.m4 (AC_FUNC_STRTOD):
* tests/fortran.at (AC_F77_DUMMY_MAIN usage):
* tests/semantics.at (AC_CHECK_DECLS):
Don’t use () in a function decl.
This change is taken from Gnulib, and is needed for apps like GDB.
* lib/autoconf/specific.m4 (_AC_SYS_YEAR2038_TEST_INCLUDES)
(_AC_SYS_YEAR2038, AC_SYS_YEAR2038): New macros, taken (with
renaming) from Gnulib.
(_AC_SYS_LARGEFILE_MACRO_VALUE): #undef before #define.
(AC_SYS_LARGEFILE): Prefer AS_IF and AS_CASE to doing it by hand.
Widen time_t if possible, too. Define __MINGW_USE_VC2005_COMPAT
early if needed.
* lib/autoconf/c.m4 (AC_C_BIGENDIAN): Improve the
inherently-unportable grep trick well enough to survive gcc
-std=c11 -flto when cross-compiling (sr#110687).
Tests of AC_{CHECK_,}HEADER_STDBOOL were failing on Darwin for two
reasons: an m4 quoting bug in tests/local.at causing Darwin sed to
throw syntax errors, and an excessively precise interpretation of how
C99 and C++11 interact. The latter is worth mentioning in NEWS.
* tests/local.at (_AT_DEFINES_CMP_PRUNE): Insert [] before ‘dnl’ in
two places to keep it separate from the result of the m4_bpatsubsts
operation that immediately precedes it.
* lib/autoconf/headers.m4 (AC_CHECK_HEADER_STDBOOL): Allow ‘bool’,
‘true’, and ‘false’ not to be macros, after including stdbool.h,
whenever __cplusplus is defined.
* NEWS: Document change to AC_{CHECK_,}HEADER_STDBOOL.
The minimum Perl version was raised to 5.8.0 from 5.6.0 in commit
3a9802d601 (but not documented as
such until e8c2d79ec4, and not
actually *enforced* by our own configure script until, er, now)
in order to use Time::HiRes::stat.
Unfortunately, while the Time::HiRes *module* was added in 5.8.0, it
did not export a ‘stat’ function until 5.8.9. More precisely, this
feature was added to Time::HiRes in version 1.92 of that module; Perl
core 5.8.8 shipped Time::HiRes 1.86, 5.8.9 shipped 1.9715. The only
system I have convenient access to, that has older Perls installed,
offers me a choice of 5.8.8 or 5.10.1, so the new requirement means
I cannot test with 5.8.x anymore.
Per https://perldoc.perl.org/perlhist the release history of these
versions of Perl is, in chronological order,
5.8.0 2002-Jul-18
5.8.8 2006-Jan-31
5.10.0 2007-Dec-18
5.8.9 2008-Dec-14 <-- almost a year later than 5.10.0
5.10.1 2009-Aug-22
5.12.0 2010-Apr-12
Per https://perldoc.perl.org/perl5101delta the differences between
5.10.0 and 5.10.1 are small, and do not make me worry about
accidentally introducing code that works on my test boxes but not for
our users, unlike the gulf between 5.8.x and 5.10.x.
Requiring 5.10 will mean that we have access to Digest::SHA, the //
and //= operators, the regexp \K escape, and ‘state’ variables
(lexical scope, persistent value) all of which I can think
of uses for (but none of them are actually used in this patch).
Putting it all together, I think a requirement bump to version 5.10.0
is justified. We are already chopping off the trailing edge at 2006
due to the requirement for M4 1.4.8 (/de facto/ since 2.70) and late
2007 is still 15 years ago.
This patch also makes configure search $PATH for executables named
‘perl5*’ and ‘perl-5.*’ if bare ‘perl’ is too old. To do this, it
introduces a helper macro AClocal_PATH_PROG_GLOBS_FEATURE_CHECK, which
I would *like* to promote to a new Autoconf feature, but I got stuck
on quoting issues — see comments in m4/perl-time-hires.m4.
* NEWS: Document requirement for Perl 5.10.
* m4/perl-time-hires.m4: New file.
* configure.ac: Use AC_PATH_PERL_WITH_TIME_HIRES_STAT to probe for
perl.
* build-aux/fetch.pl (fetch): For .pm files fetched from Automake,
rewrite “use 5.006” to “use 5.010”.
* build-aux/help-extract.pl
* lib/Autom4te/C4che.pm
* lib/Autom4te/ChannelDefs.pm
* lib/Autom4te/Channels.pm
* lib/Autom4te/Config.pm
* lib/Autom4te/Configure_ac.pm
* lib/Autom4te/FileUtils.pm
* lib/Autom4te/General.pm
* lib/Autom4te/Getopt.pm
* lib/Autom4te/Request.pm
* lib/Autom4te/XFile.pm
* tests/mktests.pl: Change “use 5.006” to “use 5.010”.
* lib/autoconf/functions.m4 (AC_FUNC_ALLOCA): Simplify and use
AS_IF. Had I done it this way originally I would have avoided the
bug that Jim just fixed.
"autoconf quoting is a pain"
* lib/autoconf/functions.m4 (AC_FUNC_ALLOCA): Its AC_CACHE_CHECK
contains an if/else block, but the closing "fi" lay just after its ")".
Before, this error didn't trigger any failure because the if/else code was
in the "else" block of AC_CACHE_CHECK's AS_IF invocation and AS_IF was also
implemented using an if..fi block. So the ostensibly-"outer" "fi" provided
by AS_IF matched the inner "if/else", and that stray-after-end "fi" served
to close the AS_IF block. However, when AS_IF switched from if..fi to
case..esac, this became a nesting error: no matching "fi".
Initially-harmless error introduced by v2.69-52-gfd29dbd7 in 2012.
Error exposed by v2.72a-30-gc8d6d6eb.
* tests/mktests.pl (scan_m4_files): Do not elide direct test
of AC_FUNC_ALLOCA.
FTR, here's the list of macros whose direct tests were being suppressed:
AC_CANONICAL_BUILD AC_CANONICAL_HOST AC_CANONICAL_TARGET
AC_CHECK_INCLUDES_DEFAULT AC_DISABLE_OPTION_CHECKING
AC_ERLANG_NEED_ERL AC_ERLANG_NEED_ERLC AC_ERLANG_SUBST_ERTS_VER
AC_ERLANG_SUBST_INSTALL_LIB_DIR AC_ERLANG_SUBST_LIB_DIR AC_F77_DUMMY_MAIN
AC_F77_LIBRARY_LDFLAGS AC_FC_DUMMY_MAIN AC_FC_LIBRARY_LDFLAGS
AC_FUNC_ALLOCA AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK AC_GNU_SOURCE
AC_HEADER_DIRENT AC_HEADER_SYS_WAIT AC_PATH_X AC_PROG_CPP AC_PROG_CXX
AC_PROG_CXXCPP AC_PROG_F77 AC_PROG_FC AC_PROG_GO AC_PROG_GREP
AC_PROG_OBJC AC_PROG_OBJCPP AC_PROG_OBJCXX AC_PROG_OBJCXXCPP
AC_STRUCT_TM AC_TYPE_GETGROUPS AC_TYPE_LONG_LONG_INT AC_TYPE_MBSTATE_T
AC_TYPE_PID_T AC_TYPE_SIZE_T AC_TYPE_UID_T AC_TYPE_UNSIGNED_LONG_LONG_INT
AC_USE_SYSTEM_EXTENSIONS
Also, port AC_EGREP_CPP to AT&T UnixPC.
Latter problem reported by Alain Knaff [sr #110657].
* lib/autoconf/general.m4 (AC_EGREP_CPP): Use new _AC_PROG_GREP.
Work even if the pattern starts with "-".
* lib/autoconf/programs.m4 (_AC_PROG_GREP):
New optional arg ACTION-IF-NOT-FOUND.
(_AC_PROG_EGREP_TRADITIONAL): New macro.
* lib/m4sugar/m4sh.m4: Work around bug in ancient sed.
Problem reported by Alain Knaff [sr#110654] for AT&T 3b1.
The Autoconf manual says this sed bug also occurs for
RISC/OS and IRIX 5.3.
Problem reported by Raphael Isemann in:
https://lists.gnu.org/r/autoconf-patches/2022-03/msg00007.html
* lib/autoconf/c.m4 (_AC_C_C99_TEST_MAIN, AC_C_FLEXIBLE_ARRAY_MEMBER):
* tests/data/gnulib_std_gnu11_2020_08_17.m4 (_AC_C_C99_TEST_HEADER):
Free storage allocated via malloc, to pacify overly-picky
implementations that issue false alarms about memory leaks.
Problem reported by Peter Johansson in:
https://lists.gnu.org/r/bug-autoconf/2022-03/msg00009.html
The bug was introduced in 2020-11-15T18:56:18Z!zackw@panix.com
with commit message saying “If anyone has a better idea for how to
make this work I will be glad to hear it”, and this patch uses a
trick with ‘case’ that should be a better idea.
* lib/m4sugar/m4sh.m4 (as_nop, as_fn_nop, _AS_EMPTY_ELSE_PREPARE):
Remove. All uses removed.
(_AS_IF_ELSE): Wrap the non-blank IF-ELSE inside a no-op case,
which works since a case branch can be empty in the shell.
* tests/m4sh.at (AS_IF and AS_CASE): Test the fix.
Problem reported by mirabilos via Eric Blake in:
https://www.austingroupbugs.net/view.php?id=1558https://lists.gnu.org/r/bug-autoconf/2022-02/msg00003.html
* lib/m4sugar/m4sh.m4 (_AS_TR_SH_PREPARE):
Define as_sed_sh as the sed script. All uses of as_tr_sh changed.
Define as_tr_sh as before, but only for compatibility with scripts
that mistakenly use as_tr_sh directly.
(AS_TR_CPP_PREPARE): Likewise for as_sed_cpp and as_tr_cpp.
This mirrors the existing RANLIB and related toolchain macros that
autoconf already exports. Some projects assume `ar` is available
which isn't always safe, so provide a macro that probes the full
toolchain settings.
This also makes it easier to use AC_REQUIRE with the macro instead
of duplicating the AC_CHECK_TOOL call in projects.
* lib/autoconf/programs.m4 (AC_PROG_AR): New macro.
* doc/autoconf.texi: Document it.
* tests/local.at (_AT_CHECK_ENV): Allow $AR output variable.
This simplifies the Makefile a bit and also paves the way for a
bootstrap script (replacing the process of re-running autoreconf with
the just-built autoconf) which will be able to cope with generated
files that get installed in @pkgdatadir@ but not in @pkgdatadir@/m4sugar.
* lib/version.in: New file, contents extracted from lib/local.mk.
* lib/local.mk: Do not generate version.m4 here.
* configure.ac: Generate lib/version.m4 from lib/version.in via
config.status.
* lib/freeze.mk, lib/local.mk, lib/m4sugar/m4sugar.m4:
version.m4 now lives in @pkgdatadir@ rather than @pkgdatadir@/m4sugar.
This patch adds the AC_F77_CRAY_POINTERS and AC_FC_CRAY_POINTERS macros,
which test if the Fortran compiler supports Cray pointers.
The macros are written such that the tests share a common backend
(_AC_FC_CRAY_POINTERS) which works on both F77 and FC compilers.
Wrappers are provided to address any future potential compatibility
issues.
The macros include additional tests for particular flags required by
GFortran and PGI compilers. The current set of flags is sparse, but can
be extended for other compilers if needed.
Documentation and a minimal test of the macro have been included.
Two minor variable name typos (@EXEEXT@ as @EEXEXT@) were also fixed in
two of the other Fortran tests.
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.
Problem reported by Bruno Haible (sr #110518).
* doc/autoconf.texi (Generating Sources)
(Running the Preprocessor, Running the Compiler)
(Running the Linker, Runtime): Briefly mention that the program
snippets are expanded as unquoted here-documents.
(Here-Documents): Document escaping needed in unquoted
here-documents. Remove mention of \" glitch in OpenBSD 2.7 sh;
that old system has not been supported for many years.
Remove advice that every \ must be quoted, as that sort
of quoting (though harmless) is not needed and is rarely done.
* lib/autoconf/c.m4 (AC_C_BIGENDIAN, _AC_LANG_OPENMP(Fortran 77)):
* lib/autoconf/types.m4 (AC_TYPE_LONG_LONG_INT): Properly quote
code snippets. The backslash-newline typos were harmless, and the
backslash-$ typo has unspecified behavior as per POSIX though the
typo is harmless on all shells I know of. However, Autoconf
should follow its own quoting advice.
The typo causes "ac_prog_cxx_stdcxx" to be always set to "cxx11",
regardless of whether the C++ compiler supports C++11.
Message-Id: <YJ4TXAeJcvU0oSec@FSAPPLE2215.fi.f-secure.com>
(tiny change)
Gnulib’s std-gnu11.m4 backports C11 and C++11 detection to autoconf
2.69. It does this by replacing the definitions of AC_PROC_CC and
AC_PROG_CXX and most of their subroutines. In particular, it replaces
the definitions of _AC_PROG_CC_C11, _AC_PROG_CC_C99, and _AC_C_STD_TRY,
but it does *not* replace the definition of _AC_PROG_CC_C89.
Autoconf commit 131d8c69f3 changed the
calling convention of _AC_C_STD_TRY, and changed the internal
definitions of _AC_PROG_CC_C{11,99,89} to match. If std-gnu11.m4 is
in use, our _AC_PROG_CC_C89 calls their _AC_C_STD_TRY with the new
calling convention, and this produces a syntactically invalid
configure script. (This is is fortunate: it could easily have been a
runtime malfunction that only manifested with compilers that only
implement C89, and then we might not have noticed the problem for
years.)
Gnulib commit a3b3fc85e3e632374811b27cb2111e50fa177e36 makes
std-gnu11.m4 do nothing when used with autoconf >=2.70, but older
versions of the file will circulate for years to come, so this patch
works around the problem in autoconf. It does this by renaming all of
the internal macros involved with C and C++ standard edition
detection, *except* _AC_PROG_CC_C89. AC_PROG_CC now calls
_AC_PROG_CC_STDC_EDITION, which loops over all supported editions
calling _AC_PROG_CC_STDC_EDITION_TRY, which uses the data provided by
the existing _AC_C_C${edition}_TEST_PROGRAM macros and a new set of
macros called _AC_C_C${edition}_OPTIONS to perform the test for that
edition of the standard. Similarly, AC_PROG_CXX calls
_AC_PROG_CXX_STDCXX_EDITION, which loops calling
_AC_PROG_CXX_STDCXX_EDITION_TRY, which uses data from
_AC_CXX_CXX${edition}_TEST_PROGRAM and _AC_CXX_CXX${edition}_OPTIONS.
_AC_PROG_CC_C89 is the only macro from the old set that we still
define, and its definition is reverted to what std-gnu11.m4 expects it
to be. Nothing in Autoconf proper uses it anymore.
foreign.at grows a test to verify that the compatibility stub version
of _AC_PROG_CC_C89 does its job. Since this is now the third test
involving an embedded copy of a third-party macro, I broke them all
out of foreign.at to separate files in test/data/.
In addition to fixing the breakage, this patch should make it easier
to extend C / C++ standard edition detection in the future, by getting
rid of the if-else chains in AC_PROG_CC/CXX and by disentangling the
lists of command-line options to test from the logic.
I also changed the manual to suggest people refer to the variables
‘ac_prog_cc_stdc’ and ‘ac_prog_cxx_stdcxx’ to learn which edition
of the C and C++ standards are selected; these are much easier to
work with than the ac_cv_prog_cc_cNN cache variables.
* lib/autoconf/c.m4 (_AC_C_STD_TRY, _AC_PROG_CC_C99, _AC_PROG_CC_C11)
(_AC_CXX_STD_TRY, _AC_PROG_CXX_CXX98, _AC_PROG_CXX_CXX11): Remove macro.
(_AC_C_C89_OPTIONS, _AC_C_C99_OPTIONS, _AC_C_C11_OPTIONS)
(_AC_PROG_CC_STDC_EDITION, _AC_PROG_CC_STDC_EDITION_TRY)
(_AC_CXX_CXX98_OPTIONS, _AC_CXX_CXX11_OPTIONS)
(_AC_PROG_CXX_STDCXX_EDITION, _AC_PROG_CXX_STDCXX_EDITION_TRY): New macros.
(_AC_PROG_CC_C89): Convert to compatibility stub for std-gnu11.m4.
(AC_PROG_CC): Use _AC_PROG_CC_STDC_EDITION.
(AC_PROG_CXX): Use _AC_PROG_CXX_STDCXX_EDITION.
* tests/data/ax_prog_cc_for_build_v18.m4
* tests/data/ax_prog_cxx_for_build_v3.m4
* tests/data/gnulib_std_gnu11_2020_08_17.m4: New files.
* tests/foreign.at (AX_PROG_CC_FOR_BUILD, AX_PROG_CXX_FOR_BUILD):
Remove embedded copy of ax_prog_cc_for_build_v18.m4,
ax_prog_cxx_for_build_v3.m4 respectively.
(gnulib-std-gnu11.m4): New test.
* tests/local.mk: Distribute tests/data/*.m4.
* doc/autoconf.texi (AC_PROG_CC, AC_PROG_CXX): Document use of
ac_prog_cc_stdc / ac_prog_cxx_stdcxx, respectively, to tell which
edition of the C / C++ standards are selected, instead of looking
through a series of cache variables with awkward definitions.
clang issues only a warning, not an error, when an undeclared
identifier that names a built-in function is used: for instance
char *(*p)(const char *, int) = strchr;
(with no `#include <string.h>`) is an error with most compilers,
a warning with clang. This broke the 2.69 implementation of
AC_CHECK_DECL. In commit 82ef7805fa,
we tried to work around this quirk by using -Werror, but that put us
at risk of being tripped up by other warnings. Bug 110400 reports,
for instance, that this fragment (which is roughly what you get, after
preprocessing, when AC_CHECK_DECL is applied to a function that *is*
properly declared)
extern void ac_decl (int, char *);
int main (void)
{
(void) ac_decl;
;
return 0;
}
provokes a warning from clang (and thus an error) when -Wextra-semi-stmt
has been added to CFLAGS earlier in the configure script. The extra
semicolon comes from AC_LANG_PROGRAM, and we can’t get rid of it
because we have no way of telling reliably when someone wrote
something like
AC_LANG_PROGRAM([[#include <stdio.h>]],
[[puts("hello world")]])
with no semicolon at the end of the statement; this has been
acceptable for decades. Besides, that’s just one warning, who knows
what compilers will start complaining about tomorrow?
So: change AC_CHECK_DECL to compile its programs with -fno-builtin,
instead, when the default compilation mode fails to detect an
undeclared strchr. The code is restructured so that we can try other
options as well, if we find another compiler with the same quirk but
different command-line syntax.
(All of this logic is very C-family specific, but it appears to me
that AC_CHECK_DECL has never worked with other languages, so we can
continue to live with that for now.)
Fixes bug 110400; partially reverts 82ef7805fa.
* lib/autoconf/general.m4 (_AC_UNDECLARED_WARNING): Rename to
_AC_UNDECLARED_BUILTIN. Instead of looking at diagnostic output,
loop trying to find a command-line option that makes the compiler
error out on undeclared builtins.
(_AC_CHECK_DECL_BODY): Don’t AC_REQUIRE anything here.
Make shell code language-agnostic, except for the actual test program.
Add arguments to the shell function for additional compiler options
to use.
(AC_CHECK_DECL): AC_REQUIRE _AC_UNDECLARED_BUILTIN here.
Supply $ac_{AC_LANG_ABBREV}_undeclared_builtin_options to
ac_fn_check_decl.
* tests/local.at (AT_CONFIG_CMP): Update list of variables to ignore
when comparing C and C++ configure runs.
* tests/semantics.at (AC_CHECK_DECLS): Add memcpy and strchr to
AC_CHECK_DECLS call for functions that may be known to the compiler.
* doc/autoconf.texi (AC_CHECK_DECL, AC_CHECK_DECLS): Remove note
about compiler warnings.
* lib/autoconf/functions.m4 (_AC_LIBOBJ_ALLOCA, AC_FUNC_ALLOCA):
Use ' not ` in generated comments, as per current GNU coding style.
(_AC_LIBOBJ_ALLOCA): Use plain # instead of unnecessary quadrigraph.
This patch is adapted from Gnulib.
Problem reported by Christian Biesinger in:
https://lists.gnu.org/r/bug-gnulib/2019-12/msg00159.html
* lib/autoconf/c.m4 (AC_C_RESTRICT): Port better to
Oracle Developer Studio C++ 12.5 or later.
This patch is adapted from Gnulib.
_AC_PROG_CC_C99 was using the wrong test program.
Fixes#110396, reported anonymously.
* lib/autoconf/c.m4 (_AC_PROG_CC_C99): Use the C99 test program, not
the C89 test program.
The absolute-path case in AT_TESTED had a typo in it, causing bizarre
error messages and preventing programs identified by absolute path
from being logged properly.
* lib/autotest/general.m4 (AT_TESTED): Fix typoed shell syntax in
handling of programs identified by absolute path.
The list of macros documented as being defined by
AC_USE_SYSTEM_EXTENSIONS had gotten out of sync with the actual list.
Update it thoroughly.
Also, I introduced an error into the commentary when I merged Julien
ÉLIE’s patch to define _NETBSD_SOURCE and _OPENBSD_SOURCE in
AC_USE_SYSTEM_EXTENSIONS. _OPENBSD_SOURCE does something on NetBSD
and *doesn’t* do anything on OpenBSD. This is corrected.
Clean up the code in AC_USE_SYSTEM_EXTENSIONS a bit while I’m in
there; we now had a redundant definition of _NETBSD_SOURCE (one
unconditional and one conditional on minix/config.h existing).
Reorganize the macro to make it easier to catch problems like this in
the future.
* lib/autoconf/specific.m4 (AC_USE_SYSTEM_EXTENSIONS): Reorganize;
remove redundant AC_DEFINE of _NETBSD_SOURCE; add some missing
AC_BEFOREs; use _AC_CHECK_HEADER_ONCE for header checks;
revise all commentary.
* doc/autoconf.texi (AC_USE_SYSTEM_EXTENSIONS): Update.
Makes the documentation of AC_PROG_CC consistent with the
documentation of AC_PROG_CXX. Also removes a bunch of redundant text
from c.m4 and adds lists of the headers that *can* be used in the
conformance tests, so future hackers don’t have to look them up.
* doc/autoconf.texi (AC_PROG_CC): Make description consistent with
description of AC_PROG_CXX.
* lib/autoconf/c.m4: Clean up some outdated or repetitive commentary
and add lists of the freestanding headers above the code that needs
to avoid using non-freestanding headers.
This makes the C conformance tests more consistent with the C++
conformance tests, and should also speed up cycling through the
possible options to turn on C99/C11.
Tested with gcc, clang, SunPRO C, and AIX xlc.
* lib/autoconf/c.m4 (_AC_C_C89_TEST_GLOBALS): Add preprocessor test
for __STDC__ being defined (to any value).
(_AC_C_C99_TEST_GLOBALS, _AC_C_C11_TEST_GLOBALS): Add preprocessor
test of the value of __STDC_VERSION__.
The tests for the level of the C and C++ standard supported by their
respective compilers should also avoid using any headers that are not
guaranteed to be available in the respective freestanding environment.
Unlike the previous change, the only user-visible consequence of this
one should be that C11/C99/C89/C++11/C++98 *compiler* support is now
correctly detected when the compilation target is a freestanding
environment.
This patch also refactors how we “emit [the text of the C/C++
standard-conformance test programs] only once per [configure script],
into shell variables which can then be referenced repeatedly,” from
c3853873, because editing them just a little made the M4 quotation
break. Clearly too fragile.
I believe this completes the fix for bug #110393.
* lib/autoconf/c.m4 (_AC_PROG_CC_C89, _AC_PROG_CC_C99, _AC_PROG_CC_C11)
_AC_C_C99_TEST_HEADER, _AC_C_C99_TEST_BODY): Move all test program
fragments into new macros that can be AC_REQUIREd individually:
_AC_C_C89_TEST_GLOBALS, _AC_C_C89_TEST_MAIN, _AC_C_C89_TEST_PROGRAM,
_AC_C_C99_TEST_GLOBALS, _AC_C_C99_TEST_MAIN, _AC_C_C99_TEST_PROGRAM,
_AC_C_C11_TEST_GLOBALS, _AC_C_C11_TEST_MAIN, _AC_C_C11_TEST_PROGRAM.
Each emits test code at most once, into a shell variable in the
INIT_PREPARE diversion.
Revise each test program to use only library features of the
respective standard’s freestanding environment.
(_AC_C_STD_TRY): Take the *name* of the shell variable holding the
complete test program as an argument, not the code itself. All
callers adjusted to match.
(_AC_PROG_CXX_CXX98, _AC_PROG_CXX_CXX11, _AC_CXX_STD_TRY)
(_AC_CXX_CXX98_TEST_HEADER, _AC_CXX_CXX98_TEST_BODY)
(_AC_CXX_CXX11_TEST_HEADER, _AC_CXX_CXX11_TEST_BODY): Similarly.
New macros are:
_AC_CXX_CXX98_TEST_GLOBALS, _AC_CXX_CXX98_TEST_MAIN,
_AC_CXX_CXX98_TEST_PROGRAM,
_AC_CXX_CXX11_TEST_GLOBALS, _AC_CXX_CXX11_TEST_MAIN,
_AC_CXX_CXX11_TEST_PROGRAM.
