autoconf/NEWS

Thanks to everybody who's submitted changes and additions to Autoconf!
I've incorporated some of them, and am still considering others for
future releases -- but I didn't want to postpone this release indefinitely.

Major changes in release 2.0:

** 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 $exec_prefix/lib/config.site and
  $prefix/lib/config.site to perform site or system specific initializations. 
* configure saves compiler output to ./config.log for debugging.
* New file autoconf.m4 loads the rest of the Autoconf macros.
* acsite.m4 is the new name for the system-wide aclocal.m4.
* Has the beginnings of a DejaGnu test suite.

** New macros:
* AC_CACHE_VAL to share results of tests between configure runs.
* AC_DEFUN to define macros and automatically AC_PROVIDE them.
* AC_CONFIG_AUX_DIR, AC_CANONICAL_SYSTEM, 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_CHECK_TYPE, which checks whether sys/types.h defines a given type.
* 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_SUBST_DEFAULT, to copy a variable from the configure environment into
  Makefiles with a default fallback value.

** Changed macros:
* Many macros renamed, but old names are accepted for backward compatibility.
* AC_OUTPUT adds the "automatically generated" comment after "#!" lines, 
  not before them.
* 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 and AC_CONFIG_HEADER allow you to override the input-file names.
* AC_OUTPUT automatically substitutes the values of CFLAGS, CXXFLAGS,
  CPPFLAGS, and LDFLAGS from the environment, with default values.
* AC_PROG_INSTALL looks for 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_CHECK_FUNCS and AC_CHECK_HEADERS take optional shell commands to
  execute on success.
* AC_REMOTE_TAPE and AC_RSH removed; too specific to tar and cpio, and
  better maintained with them.
* AC_HAVE_POUNDBANG replaced with AC_SYS_INTERPRETER, which doesn't
  take arguments.

** 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.
* autoreconf to recursively remake configure and configuration header
  files in a source tree.
* autoupdate to update a configure.in to use the new macro names.
* ifnames to list the symbols used in #if and #ifdef directives in a
  source tree.

** Changed utilities:
* autoheader can take pieces of acconfig.h to replace config.h.{top,bot}.

Major changes in release 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 release 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 release 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 release 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.

** Paths 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 release 1.7:

* New macro AC_OBSOLETE.
* Bugs in Makefile.in fixed.
* AC_LONG_FILE_NAMES improved.

Major changes in release 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 release 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 release 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
  path 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 filenames it outputs.  Instead, you can
  set the shell variables `gen_files' and `gen_config' to the list of
  filenames 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 release 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 release 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 release 1.1:

Added AC_STRCOLL macro.
Made AC_GETLOADAVG check for more things.
AC_OUTPUT argument is now optional.
Various bug fixes.