1 GNU Autoconf NEWS - User visible changes.
3 * Major changes in Autoconf 2.61b (????-??-??)
5 ** config.status now uses awk instead of sed also for config headers.
7 - As a side effect, AC_DEFINE and AC_DEFINE_UNQUOTED now handle multi-line
8 values, i.e., backslash-newline combinations are handled correctly.
9 Further, for config headers, the total size of values is not limited by
10 the POSIX length limit of text lines any more, only each single line.
12 ** Autoconf is now licensed under the General Public License version 3
13 or later (GPLv3+). As with earlier versions, the license includes
14 an exception clause so that you may release a configure script
15 generated by autoconf under the license of your own program.
16 FIXME - revisit this line once exception clause is finalized.
18 ** New Autoconf macros AC_OPENMP, AC_PATH_PROGS_FEATURE_CHECK, AC_VERSION.
20 ** AC_C_BIGENDIAN now supports universal binaries a la Mac OS X.
22 ** AC_C_RESTRICT now prefers to #define 'restrict' to a variant spelling
23 like '__restrict' if the variant spelling is available, as this is
24 more likely to work when mixing C and C++ code.
26 ** AC_CHECK_ALIGNOF's type argument T is now documented better: it must
27 be a string of tokens such that "T y;" is a valid member declaration
30 ** AC_CHECK_SIZEOF now accepts objects as well as types: the general rule
31 is that sizeof (X) works, then AC_CHECK_SIZEOF (X) should work.
33 ** AC_CHECK_TYPE and AC_CHECK_TYPES now work on any C type-name; formerly,
34 they did not work for function types. In C++, they now work on any
35 type-id that can be the operand of sizeof; this is similar to C,
36 except it excludes anonymous struct and union types. Formerly,
37 some (but not all) C++ types involving anonymous struct and union
38 were accepted, though this was not documented.
40 ** AC_CONFIG_LINKS now prefers to link against files in the build tree
41 if found, and it works to link against a file of the same name in
42 the source tree, even if both trees coincide.
44 ** AC_INIT no longer alters $@; regression introduced in 2.60.
46 ** AC_USE_SYSTEM_EXTENSIONS now defines _ALL_SOURCE for Interix platforms.
48 ** AS_HELP_STRING no longer underquotes its first argument.
50 ** The command 'autoconf -' now correctly processes a file from stdin.
52 ** For all of the directory arguments for 'configure', such as '--prefix'
53 or '--bindir', trailing slashes are stripped. As an example, if
54 tab completion in the user's shell appends trailing slashes, the
55 command './configure --prefix=/usr/' will still result in an
56 expanded libdir value of /usr/lib, not /usr//lib.
58 ** AT_SETUP now handles macro expansions properly when calculating line
59 length. However, as a side effect, any whitespace immediately
60 following a single-quoted comma is lost. If you previously used
61 AT_SETUP([a, b]), you could change to AT_SETUP([a,[] b]) to keep
64 ** Autotest now determines $srcdir correctly.
66 ** Autoconf now requires GNU M4 1.4.5 or later. Earlier versions of M4 have
67 a bug in macro tracing that interferes with the interaction between
68 Autoconf and Automake. GNU M4 1.4.8 or later is recommended. The
69 configure search for a working M4 is improved.
71 ** Document the m4sugar macros m4_ifndef and m4_version_compare
72 (available without documentation since at least autoconf 2.53).
73 Packages using the undocumented m4sugar macro m4_PACKAGE_VERSION
74 should consider using the new AC_VERSION instead.
76 ** Warnings are now generated by default when an installer invokes
77 'configure' with an unknown --enable-* or --with-* option.
78 These warnings can be disabled with the new AC_DISABLE_OPTION_CHECKING
79 macro, or by invoking 'configure' with --disable-option-checking.
81 ** For portability with the eventual M4 2.0, macros should no longer use
82 anything larger than $9 to refer to arguments.
84 ** Existing obsolete macros
85 The documentation for the following macros is adjusted to make it
86 more clear that they have previously been marked obsolete, as their
87 functionality can be accomplished by other macros. We have no
88 current plans to remove them from Autoconf.
90 AC_ENABLE AC_STRUCT_ST_BLKSIZE AC_STRUCT_ST_RDEV AC_WITH
92 ** Newly obsolete macros
93 The following macros have been marked obsolete, as they only
94 perform a subset of AC_USE_SYSTEM_EXTENSIONS. We have no current
97 AC_AIX AC_GNU_SOURCE AC_ISC_POSIX AC_MINIX
99 ** AC_C_LONG_DOUBLE is obsolescent.
100 The documentation now says that AC_C_LONG_DOUBLE is obsolescent: it
101 tests for problems that are so old that it is no longer of
102 practical importance on current systems. New programs need not use
103 AC_C_LONG_DOUBLE. We have no current plans to remove it.
105 * Major changes in Autoconf 2.61a (2006-12-11)
107 ** AC_FUNC_FSEEKO was broken in 2.61; it didn't make fseeko and ftello visible
108 on many platforms. This has been fixed.
110 ** AC_FUNC_SETVBUF_REVERSED is now obsolete. It is still defined for backward
111 compatibility but it does nothing. The macro was already
112 obsolescent, as the last systems to have the problem were those
113 based on SVR2, which became obsolete in 1987. The macro had bugs
114 on some modern systems and could no longer be maintained reliably
115 due to lack of ancient systems to test it on.
117 ** config.status now uses awk instead of sed for most substitutions, for speed.
119 - As a side effect multi-line values of substituted variables no
120 longer have a small limit in total size, though for portability
121 each line should not exceed the POSIX length limit for text lines.
123 - It is now documented that Makefile.in should not contain
124 overlapping variable occurrences, e.g., @VAR1@VAR2@.
125 Autoconf's behavior was always iffy in such cases, and the
126 awk implementation has changed the behavior.
128 ** Many uses of 'echo' have been rewritten so that Autoconf-generated
129 scripts have fewer problems with strings or file names containing
130 embedded special characters such as backslash or leading "-". This
131 was implemented by using `printf '%s\n' "$foo"' instead of `echo
132 "$foo"' when printf works. Due to the implementation technique
133 used, Autoconf-generated scripts now run considerably more slowly
134 on ancient implementations lacking printf. However, this should
135 not be a problem, since Autoconf-generated scripts in practice
136 invariably find a more-modern shell these days.
138 * Major changes in Autoconf 2.61 (2006-11-17)
140 ** New macros AC_C_FLEXIBLE_ARRAY_MEMBER, AC_C_VARARRAYS.
142 ** AC_ARG_ENABLE and AC_ARG_WITH now allow '.' in feature and package names.
144 * Major changes in Autoconf 2.60b (2006-10-22)
147 Autoconf-generated shell scripts no longer export BIN_SH, due to
148 configuration hassles with this. Installers who need BIN_SH in
149 their environment should set it before invoking 'configure' and
150 'make'. As far as we know, this affects only Unixware installations.
152 ** Obsolescent macros
153 The documentation now says that the following macros are obsolescent,
154 as they are superseded by Gnulib:
156 AC_FUNC_FNMATCH AC_FUNC_FNMATCH_GNU AC_FUNC_GETLOADVG AC_REPLACE_FNMATCH
158 New programs should use the Gnulib counterparts of these macros.
159 We have no current plans to remove them from Autoconf.
161 ** AC_COMPUTE_INT no longer caches or reports results.
163 ** AC_CHECK_DECL now also works with aggregate objects.
165 ** AC_USE_SYSTEM_EXTENSIONS now defines _TANDEM_SOURCE for NonStop platforms.
167 ** GNU M4 1.4.7 or later is now recommended.
170 New M4sugar macro, which is more secure than the POSIX M4 maketemp.
173 Now an alias for m4_mkstemp.
175 * Major changes in Autoconf 2.60a (2006-08-25)
177 ** GNU M4 1.4.6 or later is now recommended.
179 ** The check for C99 now tests for varargs macros, as documented.
180 It also tests that the preprocessor supports 64-bit integers.
182 ** Autoconf now uses constructs like "#ifdef HAVE_STDLIB_H" rather than
183 "#if HAVE_STDLIB_H", so that it now works with "gcc -Wundef -Werror".
185 ** The functionality of the undocumented _AC_COMPUTE_INT is now provided
186 by a public and documented macro, AC_COMPUTE_INT. The parameters to the
187 two macros are different, so autoupdate will not change the old private name
188 to the new one. _AC_COMPUTE_INT may be removed in a future release.
190 ** AC_TYPE_LONG_LONG_INT and AC_TYPE_UNSIGNED_LONG_LONG_INT now require
191 that long long types be at least 64 bits wide, as C99 and tradition
192 requires. Formerly, they accepted implementations of any width.
195 * Major changes in Autoconf 2.60
197 Released 2006-06-23, by Ralf Wildenhues.
199 ** Autoconf no longer depends on whether m4wrap is FIFO (as Posix requires)
200 or LIFO (as in GNU M4 1.4.x). GNU M4 2.0 is expected to conform to Posix
201 here, so m4wrap/m4_wrap users should no longer depend on LIFO behavior.
203 ** Provide a way to turn off warnings about the changed directory variables.
205 * Major changes in Autoconf 2.59d
207 Released 2006-06-05, by Ralf Wildenhues.
209 ** GNU make now recommended for VPATH builds
210 INSTALL now suggests VPATH builds (e.g., "sh ../srcdir/configure")
211 only if you use GNU make. In practice, other 'make' implementations
212 have too many subtle incompatibilities in their support for VPATH.
213 Many packages (including Autoconf itself) are portable to other
214 'make' implementations, but some packages are not, and recommending
215 GNU make keeps the installation instructions simpler.
217 ** Even more safety checks for the new Directory variables:
218 Warn about suspicious `${datarootdir}' found in config files output.
220 ** AC_TRY_COMMAND, AC_TRY_EVAL, ac_config_guess, ac_config_sub, ac_configure
221 These never-documented macros and variables have been marked with
222 comments saying that they may be removed in a future release,
223 because their use can lead to unintended code being executed.
224 If you need functionality that only these macros or variables
225 currently supply, please write bug-autoconf@gnu.org.
227 ** AC_SUBST, AC_DEFINE
228 Literal arguments to these are passed to m4_pattern_allow now.
231 Passing 'ac_cv_prog_cc_stdc=no' to 'configure' now sets ac_cv_prog_cc_c99
232 and ac_cv_prog_cc_c89 to 'no' as well, for backward compatibility with
233 obsolete K&R tests in the Automake test suite.
242 Now more robust with special characters in file names, or when
243 multiple processes create the same directory at the same time.
245 ** Obsolescent macros
246 The documentation now says that the following macros are obsolescent:
247 they test for problems that are so old that they are no longer of
248 practical importance on current systems.
250 AC_C_BACKSLASH_A AC_FUNC_MEMCMP AC_HEADER_DIRENT
251 AC_C_CONST AC_FUNC_SELECT_ARGTYPES AC_HEADER_STAT
252 AC_C_PROTOTYPES AC_FUNC_SETPGRP AC_HEADER_STDC
253 AC_C_STRINGIZE AC_FUNC_SETVBUF_REVERSED AC_HEADER_SYS_WAIT
254 AC_C_VOLATILE AC_FUNC_STAT AC_HEADER_TIME
255 AC_FUNC_CLOSEDIR_VOID AC_FUNC_STRFTIME AC_ISC_POSIX
256 AC_FUNC_GETPGRP AC_FUNC_UTIME_NULL AC_PROG_GCC_TRADITIONAL
257 AC_FUNC_LSTAT AC_FUNC_VPRINTF AC_STRUCT_TM
259 New programs need not use these macros. We have no current plans to
263 For compatibility with future Libtool 2.0, autoreconf will invoke
264 libtoolize with the option `--ltdl' now, if LT_CONFIG_LTDL_DIR is
267 * Major changes in Autoconf 2.59c
269 Released 2006-04-12, by Ralf Wildenhues.
271 ** The configure command now redirects standard input from /dev/null,
272 to help avoid problems with subsidiary commands that might mistakenly
273 read standard input. AS_ORIGINAL_STDIN_FD points to the original
274 standard input before this redirection, if you really want configure to
275 read from standard input.
277 ** Directory variables adjusted to recent changes in the GNU Coding Standards.
278 The following directory variables are new:
280 datarootdir read-only architecture-independent data root [PREFIX/share]
281 localedir locale-specific message catalogs [DATAROOTDIR/locale]
282 docdir documentation root [DATAROOTDIR/doc/PACKAGE]
283 htmldir html documentation [DOCDIR]
284 dvidir dvi documentation [DOCDIR]
285 pdfdir pdf documentation [DOCDIR]
286 psdir ps documentation [DOCDIR]
288 The following variables have new default values:
290 datadir read-only architecture-independent data [DATAROOTDIR]
291 infodir info documentation [DATAROOTDIR/info]
292 mandir man documentation [DATAROOTDIR/man]
294 This means that if you use any of `@datadir@', `@infodir@', or
295 `@mandir@' in a file, you will have to ensure `${datarootdir}' is
296 defined in this file. As a temporary measure, if any of those are
297 found but no mention of `datarootdir', the substitutions will be
298 replaced with values that do not contain `${datarootdir}', and a
299 warning will be issued.
301 ** @top_builddir@ is now a dir name: it is always nonempty and doesn't have
302 a trailing slash. Similar change will be made to ac_top_builddir in a
303 future release; the old style value, which matches (../)*, is (and will
304 continue to be) available as ac_top_build_prefix.
307 New macro to check for support of 'typeof' syntax a la GNU C.
309 ** AC_CHECK_DECLS_ONCE, AC_CHECK_FUNCS_ONCE, AC_CHECK_HEADERS_ONCE
310 New "once-only" variants of commonly-used macros, to make 'configure'
311 smaller and faster in common cases.
314 New macro to check for strtold with C99 semantics.
317 New macro that lets builder disable assertions at 'configure'-time.
320 Now checks for X11/Xlib.h and XrmInitialize (X proper) rather than
321 X11/Intrinsic.h and XtMalloc (Xt).
323 ** AC_PRESERVE_HELP_ORDER
324 New macro that causes `configure' to display help strings for AC_ARG_ENABLE
325 and AC_ARG_WITH arguments in one region, in the order defined. The default
326 behavior is to group options of each classes separately.
328 ** AC_PROG_CC, AC_PROG_CXX
329 No longer automatically arrange to declare the 'exit' function of C,
330 when a C++ compiler is used. Standard Autoconf macros no longer use
331 'exit', so this is no longer an issue for them. If you use C++, and
332 want to call 'exit', you'll have to arrange for its declaration
333 yourself. But we now suggest you return from 'main' instead.
335 ** AC_PROG_CC_C89, AC_PROG_CC_C99
336 New macros for ISO C99 support. AC_PROG_CC_C89 and AC_PROG_CC_C99
337 check for ANSI C89 and ISO C99 support respectively.
340 Has been unobsoleted, and will check if the compiler supports ISO
341 C99, falling back to ANSI C89 if not. ac_cv_prog_cc_stdc is
342 retained for backwards compatibility, assuming the value of
343 ac_cv_prog_cc_c99 or ac_cv_prog_cc_c89 (whichever is valid, in
346 ** AC_STRUCT_DIRENT_D_INO, AC_STRUCT_DIRENT_D_TYPE
347 New macros for checking commonly-used members of struct dirent.
350 The substituted value can now contain newlines.
353 The substitution now occurs only when @variable@ is on a line by itself,
354 optionally surrounded by spaces and tabs. The whole line is replaced.
356 ** AC_TYPE_LONG_DOUBLE, AC_TYPE_LONG_DOUBLE_WIDER
357 New macros to check for long double, and whether it is wider than double.
358 The old macro AC_C_TYPE_LONG_DOUBLE has been marked as obsolete;
359 applications should switch to the new macro.
361 ** AC_TYPE_INT8_T, AC_TYPE_INT16_T, AC_TYPE_INT32_T, AC_TYPE_INT64_T,
362 AC_TYPE_INTMAX_T, AC_TYPE_INTPTR_T, AC_TYPE_LONG_LONG_INT, AC_TYPE_SSIZE_T,
363 AC_TYPE_UINT8_T, AC_TYPE_UINT16_T, AC_TYPE_UINT32_T, AC_TYPE_UINT64_T,
364 AC_TYPE_UINTMAX_T, AC_TYPE_UINTPTR_T, AC_TYPE_UNSIGNED_LONG_LONG_INT
365 New macros to check for C99 and POSIX types.
367 ** AC_USE_SYSTEM_EXTENSIONS
368 New macro to enable extensions to Posix.
371 New macro which is defined to the name of the first declared config header
372 or undefined if no config headers have been declared yet.
375 The macro correctly handles quadrigraphs now.
377 ** AS_BOURNE_COMPATIBLE, AS_SHELL_SANITIZE, AS_CASE
378 These macros are new or published now.
381 New macro for copyright notices in testsuite files.
383 ** ALLOCA, LIBOBJS, LTLIBOBJS
384 Object names added to these variables are now prefixed with `${LIBOBJDIR}',
385 as in `${LIBOBJDIR}alloca.o'. LIBOBJDIR is meant to be defined from
386 `Makefile.in' in case the object files lie in a different directory.
387 The LIBOBJDIR feature is experimental.
390 Supports --no-recursive now.
392 ** New macros to support Erlang/OTP.
393 New macros for configuring paths to Erlang tools and libraries:
394 AC_ERLANG_PATH_ERLC, AC_ERLANG_NEED_ERLC, AC_ERLANG_PATH_ERL,
395 AC_ERLANG_NEED_ERL, AC_ERLANG_CHECK_LIB, AC_ERLANG_SUBST_ROOT_DIR,
396 AC_ERLANG_SUBST_LIB_DIR.
398 New macros for configuring installation of Erlang libraries:
399 AC_ERLANG_SUBST_INSTALL_LIB_DIR, AC_ERLANG_SUBST_INSTALL_LIB_SUBDIR.
401 ** The manual now mentions Gnulib more prominently.
403 ** New macros to support Objective C.
404 AC_PROG_OBJC, AC_PROG_OBJCPP.
406 * Major changes in Autoconf 2.59b
408 Released 2004-08-20, by Paul Eggert.
411 New macro that computes the default alignment of a type.
413 ** AC_CHECK_TOOL, AC_PATH_TOOL, AC_CHECK_TOOLS
414 When cross-compiling, these macros will give a warning if the tool
415 is not prefixed. In the future, unprefixed cross tools will not
416 be detected; please consult the info documentation for information
417 about the reason of this change.
419 ** AC_CHECK_TARGET_TOOL, AC_PATH_TARGET_TOOL, AC_CHECK_TARGET_TOOLS
420 New macros that detect programs whose name is prefixed with the
421 target type, if the build type and target type are different.
423 ** AC_REQUIRE_AUX_FILE
424 New trace macro that declares expected auxiliary files.
427 New macro that tests for a grep program that accepts as a long a line
430 ** AC_PROG_EGREP, AC_PROG_FGREP
431 These macros now require AC_PROG_GREP, and try EGREP="$GREP -E" and
432 FGREP="$GREP -F" respectively if possible, or else run a path search for
433 a program that accepts as long a line as possible.
436 New macro that tests for a sed program that truncates as few characters
439 * Major changes in Autoconf 2.59
441 Released 2003-11-04, by Akim Demaille
443 ** ac_abs_builddir etc.
444 Absolute file names were actually relative in 2.58.
446 * Major changes in Autoconf 2.58
448 Released 2003-11-04, by Akim Demaille
451 core.* files are no longer removed, as they may be valid user files.
453 ** autoreconf and auxiliary directory
454 Autoreconf creates the auxiliary directory if needed. This is
455 especially useful for initial "bootstrapping" of fresh CVS checkouts.
457 ** AC_CONFIG_MACRO_DIR
458 Use this macro to declare the directory for local M4 macros for aclocal.
461 No longer includes twice the same file in LIBOBJS if invoked
464 ** AC_CONFIG_COMMANDS
465 The directory for its first argument is automatically created. For
468 AC_CONFIG_COMMANDS([src/modules.hh], [...])
470 $top_builddir/src/ is created if needed.
472 ** Autotest and local.at
473 The optional file local.at is always included in Autotest test suites.
476 The warnings are always issued, including with cached runs.
477 This became a significant problem since aclocal and automake can
478 run autoconf behind the scene.
480 ** autoheader warnings
481 The warnings of autoheader can be turned off, using --warning.
482 For instance, -Wno-obsolete disables the complaints about acconfig.h
483 and other deprecated constructs.
486 AC_C_RESTRICT, AC_INCLUDES_DEFAULT, AC_LANG_ASSERT, AC_LANG_WERROR,
489 ** AC_DECL_SYS_SIGLIST
493 Now checks that mktime is the inverse of localtime.
495 ** Improve DJGPP portability
496 The Autoconf tools and configure behave better under DJGPP.
498 ** Present But Cannot Be Compiled
499 New FAQ section dedicated to the mystic
501 configure: WARNING: pi.h: present but cannot be compiled
502 configure: WARNING: pi.h: check for missing prerequisite headers?
503 configure: WARNING: pi.h: proceeding with the preprocessor's result
506 ** Concurrent executions of autom4te
507 autom4te now locks its internal files, which enables concurrent
508 executions of autom4te, likely to happen if automake, autoconf,
509 autoheader etc. are run simultaneously.
512 Use of Libtool 1.5 and higher is encouraged. Compatibility with
513 Libtool pre-1.4 is not checked.
516 Testsuites no longer rerun failed tests in verbose mode; instead,
517 failures are logged while the test is run.
519 In addition, expected failures can be marked as such.
521 * Major changes in Autoconf 2.57
523 Released 2002-12-03 by Paul Eggert.
525 Bug fixes for problems with AIX linker, with freestanding C compilers,
526 with GNU M4 limitations, and with obsolete copies of GNU documents.
528 The Free Documentation License has been upgraded from 1.1 to 1.2.
530 * Major changes in Autoconf 2.56
532 Released 2002-11-15 by Akim Demaille.
534 One packaging problem fixed (config/install-sh was not executable).
536 * Major changes in Autoconf 2.55
538 Released 2002-11-14 by Akim Demaille.
542 Have your configure.ac checked by autoscan ("autoscan").
543 Try the warning options ("autoreconf -fv -Wall").
547 - AC_CHECK_HEADER, AC_CHECK_HEADERS
548 More information on proper use.
550 - Writing Test Programs
552 This sections explains how to write good test sources to use with
553 AC_COMPILE_IFELSE etc. It documents AC_LANG_PROGRAM and so forth.
555 - AC_FOO_IFELSE vs. AC_TRY_FOO
557 Explains why Autoconf moves from AC_TRY_COMPILE etc. to
558 AC_COMPILE_IFELSE and AC_LANG_PROGRAM etc.
562 - Is more robust to different Gettext installations.
564 - Produces messages (when --verbose) to be understood by Emacs'
567 - Supports -W/--warnings.
570 Once the GNU Build System reinstalled, run `./config.status
571 --recheck && ./config.status && make' if possible.
575 - Supports --cache, and --no-cache.
577 - ~/.autom4te.cfg makes it possible to disable the caching mechanism
578 (autom4te.cache). See `Customizing autom4te' in the documentation.
585 Support for the obsoleted options -m, --macrodir, -l, --localdir is
586 dropped in favor of the safer --include/--prepend-include scheme.
591 AC_COMPILER_IFELSE, AC_FUNC_MBRTOWC, AC_HEADER_STDBOOL,
592 AC_LANG_CONFTEST, AC_LANG_SOURCE, AC_LANG_PROGRAM, AC_LANG_CALL,
593 AC_LANG_FUNC_TRY_LINK, AC_MSG_FAILURE, AC_PREPROC_IFELSE.
596 Obsoleted macros are kept for Autoconf backward compatibility, but
597 should be avoided in configure.ac. Running autoupdate is advised.
600 - AC_DEFINE/AC_DEFINE_UNQUOTED
602 We have to stop using the old compatibility scheme --that tried to
603 avoid useless backslashes-- because Libtool 1.4.3 contains a
605 AC_DEFINE([error_t], [int],
606 [Define to a type to use for \`error_t' if it is not
607 otherwise available.])
609 We have to quote the single quotes and backslashes with \. The old
610 compatibility scheme saw that ` was backslashed, and therefore did
611 not quote the single quote... Failure. Hence, Autoconf 2.54 is not
612 compatible with Libtool. Autoconf 2.55 is, but in some cases might
613 produce more \ than wanted.
615 Please, note that in the future the same problem will happen with
616 AC_MSG_*: use `autoreconf -f -Wall'.
620 - Portability of the Autoconf package to Solaris.
622 - Spurious warnings caused by config.status.
623 This bug is benign, but painful: on some systems (typically
624 FreeBSD), warnings such as:
626 config.status: creating Makefile
627 mv: Makefile: set owner/group (was: 1357/0): Operation not permitted
629 could be issued. This is fixed.
632 Simultaneous executions of config.status are possible again.
634 - Precious variables accumulation
636 config.status could stack several copies of the precious variables
640 ** Plans for later versions
644 The compatibility hooks with the old scheme will be completely
645 removed. Please, advice/use `--build', `--host', and `--target'
648 - AC_CHECK_HEADER, AC_CHECK_HEADERS
650 The tests will be stricter, please make sure your invocations are
655 Shell functions will gradually be introduced, probably starting with
656 Autotest. If you know machines which are in use that you suspect
657 *not* to support shell functions, please run the test suite of
658 Autoconf 2.55 on it, and report the results to
659 bug-autoconf@gnu.org.
663 Special characters in AC_MSG_* need not be quoted. Currently,
664 Autoconf has heuristics to decide when a string is escaped, or has
665 to be escaped. This scheme is fragile, and will be removed; the
666 only risk is uglified messages. Please, run `autoreconf -f -Wall'
667 to find occurrences that will be affected.
669 * Major changes in Autoconf 2.54
671 Released 2002-09-13 by Akim Demaille.
675 - autoreconf no longer changes the version of the gettext/po/intl
676 support files. It now adds the files the correspond to the
677 AM_GNU_GETTEXT_VERSION declared in configure.ac.
679 Warning: It now relies on the 'autopoint' program, which is part
680 of GNU gettext 0.11.4 and newer.
682 Please note that you need to have a GNU gettext version that
683 corresponds at least to the AM_GNU_GETTEXT_VERSION declared
684 in configure.ac. You can upgrade to newer GNU gettext versions,
685 though, without needing to change configure.ac.
687 - The -I DIR or --include=DIR option now appends DIR to the include path
688 instead of prepending; this is for consistency with other GNU tools.
689 The new -B DIR or --prepend-include=DIR option has the old behavior.
694 Now handles all the gory details about LIBOBJS and LTLIBOBJS.
695 Please, remove lines such as
697 # This is necessary so that .o files in LIBOBJS are also
698 # built via the ANSI2KNR-filtering rules.
699 LIBOBJS=`echo $LIBOBJS|sed 's/\.o /\$U.o /g;s/\.o$/\$U.o/'`
701 and read the `AC_LIBOBJ vs LIBOBJS' section. Do not define U in
702 your Makefiles either.
704 - AC_CONFIG_LINKS now makes copies if it can't make links.
706 - AC_FUNC_FNMATCH now tests only for POSIX compatibility, reverting to
707 Autoconf 2.13 behavior. The new macro AC_FUNC_FNMATCH_GNU also
708 tests for GNU extensions to fnmatch, and replaces fnmatch if needed.
710 - AC_FUNC_SETVBUF_REVERSED no longer fails when cross-compiling.
712 - AC_PROG_CC_STDC is integrated into AC_PROG_CC.
714 - AC_PROG_F77 default search no longer includes cf77 and cfg77.
718 AC_C_BACKSLASH_A, AC_CONFIG_LIBOBJ_DIR, AC_GNU_SOURCE,
719 AC_PROG_EGREP, AC_PROG_FGREP, AC_REPLACE_FNMATCH,
720 AC_FUNC_FNMATCH_GNU, AC_FUNC_REALLOC, AC_TYPE_MBSTATE_T.
723 looks for getloadavg.c in the CONFIG_LIBOBJ_DIR.
726 Now defines HAVE_MALLOC to 0 if `malloc' does not work, and asks
727 for an AC_LIBOBJ replacement.
731 - Spurious complaints from `m4_bmatch' about invalid regular
732 expressions are suppressed.
734 - Empty top_builddirs are properly handled.
736 - AC_CHECK_MEMBER works correctly when the member is an aggregate.
739 Now colon in the optional path arguments are properly handled.
741 ** Improved portability
743 - Both Autoconf the package, and the scripts it produces, should run
744 more reliably with Zsh. Bear in mind it is the default Bourne shell
747 - Autoconf and the scripts it produces no longer assume the existence of
748 the obsolescent commands egrep and fgrep.
752 - Limitations of Make
756 The GNATS base moved to
757 http://bugs.gnu.org/cgi-bin/gnatsweb.pl?database=autoconf
758 (It is no longer available, though.)
763 Now contains the list of ouput variables and files (AC_SUBST,
766 * Major changes in Autoconf 2.53
768 Released 2002-03-08 by Akim Demaille.
772 Perl 5.005_03 or later is required: autom4te is written in Perl and is
773 needed by autoconf. autoheader, autoreconf, ifnames, and autoscan are
779 Argument requirements, output variables, defined macros.
780 - M4sugar, M4sh, Autotest
782 - Double quoting macros
783 AC_TRY_CPP, AC_TRY_COMPILE, AC_TRY_LINK and AC_TRY_RUN.
785 The Autoconf manual is now distributed under the terms of the GNU FDL.
786 - Section `Hosts and Cross-Compilation'
787 Explains the rationale for the 2.5x changes in the cross-compilation
788 chain, and in the relationships between build, host, and target
790 Emphasizes that `cross-compilation' == `--host is given'.
791 If you are working on compilers etc., be sure to read this section.
792 - Section `AC_LIBOBJ vs. LIBOBJS'
793 Explains why assigning LIBOBJS directly is now an error.
794 Details how to update the code.
799 Now used instead of hard coded line numbers.
800 This eases the comparison of `configure's, and diminishes the
801 pressure over control version archives.
802 Automatic replacement for shells that don't support this feature.
803 - New output variables
804 @builddir@, @top_builddir@, @abs_srcdir@, @abs_top_srcdir@, @abs_builddir@,
809 Autoconf and Autotest modes are provided.
814 New, used by the Autoconf suite to cache and speed up most processing.
816 Supported by autom4te, autoconf and autoheader.
818 Replaces --autoconf-dir and --localdir in autoconf, autoheader,
819 autoupdate, and autoreconf.
821 No longer passes --cygnus, --foreign, --gnits, --gnu, --include-deps:
822 automake options are to be given via AUTOMAKE_OPTIONS.
824 Runs gettextize and libtoolize when appropriate.
826 --m4dir is no longer supported.
828 Now runs only in the specified directories, defaulting to `.',
829 but understands AC_CONFIG_SUBDIRS for dependent directories.
830 Before, it used to run on all the `configure.ac' found in the
832 Independent packages are properly updated.
836 - The top level $prefix is propagated to the AC_CONFIG_SUBDIRS configures.
838 Under the user pressure, $? is finally available. Probably a mistake.
839 - AC_F77_LIBRARY_LDFLAGS now supports the HP/UX f90 compiler.
840 - Precious variables accumulation
841 config.status could stack several copies of the precious variables
843 - AC_PATH_PROG and family.
844 Works properly when given a literal path.
846 Somewhere since 2.13, the result had been reversed.
850 - AC_C_BIGENDIAN supports the cross-compiling case.
851 - AC_C_BIGENDIAN accepts ACTION-IF-TRUE, ACTION-IF-FALSE, and
852 ACTION-IF-UNKNOWN arguments. All are facultative, and the default
853 for ACTION-IF-TRUE is to define WORDS_BIGENDIAN like AC_C_BIGENDIAN
855 - AC_C_LONG_DOUBLE now succeeds only if `long double' has more range or
856 precision than `double'.
861 It now defines the preprocessor symbols PACKAGE_NAME,
862 PACKAGE_TARNAME, PACKAGE_VERSION, PACKAGE_STRING, and
866 Admits a fourth optional parameter: the tar name.
868 - AC_CONFIG_COMMANDS, HEADERS, FILES, LINKS.
869 Provide the user with srcdir, ac_srcdir, ac_top_srcdir, ac_builddir,
870 ac_top_builddir, ac_abs_srcdir, ac_abs_top_srcdir, ac_abs_builddir,
873 - AC_CONFIG_COMMANDS, HEADERS, FILES, LINKS and AC_OUTPUT.
874 Are much less expensive when using long lists of files.
877 Works with shell variables, and non alphanumeric names.
881 - AC_FUNC_STRERROR_R now sets STRERROR_R_CHAR_P, not HAVE_WORKING_STRERROR_R,
882 because POSIX 1003.1-200x draft 7 says strerror_r returns int, not char *.
884 - AC_FUNC_STRTOD substitutes POW_LIB.
889 * Major changes in Autoconf 2.52
891 Released 2001-07-18 by Akim Demaille.
896 This feature was present in autoconf 2.50 but was not documented.
897 For example, `@<:@' is translated to `[' just before output. This
898 is useful when writing strings that contain unbalanced quotes, or
899 other hard-to-quote constructs.
900 - m4_pattern_forbid, m4_pattern_allow
901 - Tips for upgrading from 2.13.
902 - Using autoscan to maintain a configure.ac.
905 - Now include stdint.h.
906 - sys/types.h and sys/stat.h are guarded.
907 - strings.h is included if available, and not conflicting with string.h.
910 - The test suite is more robust and presents less false failures.
911 - Invocation of GNU M4 now robust to POSIXLY_CORRECT.
912 - configure accepts --prefix='' again.
913 - AC_CHECK_LIB works properly when its first argument is not a
915 - HAVE_INTTYPES_H is defined only if not conflicting with sys/types.h.
916 - build_, host_, and target_alias are AC_SUBST as in 2.13.
917 - AC_ARG_VAR properly propagates precious variables inherited from the
918 environment to ./config.status.
919 - Using --program-suffix/--program-prefix is portable.
920 - Failures to detect the default compiler's output extension are less
922 - `config.status foo' works properly when `foo' depends on variables
923 set in an AC_CONFIG_THING INIT-CMD.
924 - autoheader is more robust to broken input.
925 - Fixed Fortran name-mangling and link tests on a number of systems,
926 e.g. NetBSD; see AC_F77_DUMMY_MAIN, below.
929 - AC_CHECK_HEADER and AC_CHECK_HEADERS support a fourth argument to
930 specify pre-includes. In this case, the headers are compiled with
931 cc, not merely preprocessed by cpp. Therefore it is the _usability_
932 of a header which is checked for, not just its availability.
933 - AC_ARG_VAR refuses to run configure when precious variables have
935 - Versions of compilers are dumped in the logs.
936 - AC_CHECK_TYPE recognizes use of `foo_t' as a replacement type.
939 - AC_PATH_XTRA only adds -ldnet to $LIBS if it's needed to link.
940 - AC_FUNC_WAIT3 and AC_SYS_RESTARTABLE_SYSCALLS are obsoleted.
941 - AM_FUNC_ERROR_AT_LINE, AM_FUNC_FNMATCH, AM_FUNC_MKTIME,
942 AM_FUNC_OBSTACK, and AM_FUNC_STRTOD are now activated.
943 Be sure to read `Upgrading from Version 2.13' to understand why
944 running `autoupdate' is needed.
945 - AC_F77_DUMMY_MAIN, AC_F77_MAIN: new macros to detect whether
946 a main-like routine is required/possible when linking C/C++ with
947 Fortran. Users of e.g. AC_F77_WRAPPERS should be aware of these.
948 - AC_FUNC_GETPGRG behaves better when cross-compiling.
950 * Major changes in Autoconf 2.51
951 There was no release of Autoconf 2.51 since some packagers had used
952 this version number without permission to ship intermediary versions
953 of 2.50. The version was skipped to avoid confusion.
955 * Major changes in Autoconf 2.50
957 Released 2001-05-21 by Akim Demaille.
960 There have been far too many to enumerate them here. Check out
961 ChangeLog if you really want to know more.
963 ** Improved documentation
964 In particular, portability issues are better covered.
967 All the standard GNU Makefile targets are supported. The layout has
968 changed: m4/ holds the M4 extensions Autoconf needs for its
969 configuration, doc/ contains the documentation, and tests/ contains
972 ** Man pages are provided
973 For autoconf, autoreconf, autoupdate, autoheader, autoscan, ifnames,
974 config.guess, config.sub.
978 Provides a safe and powerful means to trace the macro uses. This
979 provide the parsing layer for tools which need to `study'
983 Specify what category of warnings should be enabled.
985 - When recursing into subdirectories, try for configure.gnu before
986 configure to adapt for packages not using autoconf on case-insensitive
990 More errors are now caught (circular AC_REQUIRE dependencies,
991 AC_DEFINE in the action part of an AC_CACHE_CHECK, too many pops
992 etc.). In addition, their location and call stack are given.
995 autoupdate is much more powerful, and is able to provide the glue code
996 which might be needed to move from an old macro to its newer
999 You are strongly encouraged to use it to modernize both your
1000 `configure.in' and your .m4 extension files.
1003 The internal machinery of autoheader has completely changed. As a
1004 result, using `acconfig.h' should be considered to be obsoleted, and
1005 you are encouraged to get rid of it using the AH macros.
1010 ** Fortran 77 compilers
1011 Globally, the support for Fortran 77 is considerably improved.
1013 Support for automatically determining a Fortran 77 compiler's
1014 name-mangling scheme. New CPP macros F77_FUNC and F77_FUNC_ are
1015 provided to wrap C/C++ identifiers, thus making it easier and more
1016 transparent for C/C++ to call Fortran 77 routines, and Fortran 77 to
1017 call C/C++ routines. See the Texinfo documentation for details.
1020 The test suite no longer uses DejaGNU. It should be easy to submit
1021 test cases in this new framework.
1024 - --help, --help=long, -hl
1025 no longer dumps useless items.
1027 lists only specific options.
1028 - --help=recursive, -hr
1029 displays the help of all the embedded packages.
1030 - Remembers environment variables when reconfiguring.
1031 The previous scheme to set envvar before running configure was
1033 what prevented configure from remembering the environment in which
1034 it was run, therefore --recheck was run in an inconsistent
1035 environment. Now, one should run
1037 and then --recheck will work properly. Variables declared with
1038 AC_ARG_VAR are also preserved.
1040 $build defaults to `config.guess`, $host to $build, and then $target
1042 Cross-compilation is a global status of the package, it no longer
1043 depends upon the current language.
1044 Cross compilation is enabled iff the user specified `--host'.
1045 `configure' now fails if it can't run the executables it compiles,
1046 unless cross-compilation is enabled.
1048 The cache file is disabled by default. The new options
1049 `--config-cache', `-C' set the cache to `config.cache'.
1053 Much faster on most architectures.
1054 - concurrent executions
1055 It is safe to use `make -j' with config.status.
1056 - human interface improved
1057 It is possible to invoke
1058 ./config.status foobar
1059 instead of the former form (still valid)
1060 CONFIG_COMMANDS= CONFIG_HEADERS= CONFIG_LINKS= \
1061 CONFIG_FILES=foobar:foo.in:bar.in \
1063 The same holds for configuration headers and links.
1064 You can instantiate unknown files and headers:
1065 ./config.status --header foo.h:foo.h.in --file bar:baz
1066 - has a useful --help
1067 - accepts special file name "-" for stdin/stdout
1072 Specify additional copyright information.
1075 Now expects the identity of the package as argument.
1079 Most macros, if not all, now strictly follow the `one quotation
1080 level' rule. This results in a more predictable expansion.
1083 A sly bug in the AC_REQUIRE machinery, which could produce incorrect
1084 configure scripts, was fixed by Axel Thimm.
1088 Document and ask for the registration of an envvar.
1091 Specifies the file which `configure' should look for when trying to
1092 find the source tree (used to be handled by AC_INIT).
1094 - AC_CONFIG_COMMANDS
1095 To add new actions to config.status. Should be used instead of
1099 Replaces AC_LINK_FILES.
1101 - AC_CONFIG_HEADERS, AC_CONFIG_COMMANDS, AC_CONFIG_SUBDIRS,
1102 AC_CONFIG_LINKS, and AC_CONFIG_FILES
1103 They now obey sh: you should no longer use shell variables as
1104 argument. Instead of
1106 test "$package_foo_enabled" = yes && $my_subdirs="$my_subdirs foo"
1107 AC_CONFIG_SUBDIRS($my_subdirs)
1111 if test "$package_foo_enabled" = yes; then
1112 AC_CONFIG_SUBDIRS(foo)
1116 To format an Autoconf macro's help string so that it looks pretty
1117 when the user executes `configure --help'.
1120 ** Generic Test Macros
1122 The interface of the AC_CHECK families of macros (decl, header,
1123 type, member, func) is now uniform. They support the same set of
1126 - AC_CHECK_DECL, AC_CHECK_DECLS
1127 To check whether a symbol is declared.
1129 - AC_CHECK_SIZEOF, AC_C_CHAR_UNSIGNED.
1130 No longer need a cross-compilation default.
1133 The test it performs is much more robust than previously, and makes
1134 it possible to test builtin types in addition to typedefs.
1135 It is now schizophrenic:
1136 - AC_CHECK_TYPE(TYPE, REPLACEMENT)
1137 remains for backward compatibility, but its use is discouraged.
1138 - AC_CHECK_TYPE(TYPE, IF-FOUND, IF-NOT-FOUND, INCLUDES)
1139 behaves exactly like the other AC_CHECK macros.
1142 Checks whether given types are supported by the system.
1144 - AC_CHECK_MEMBER, AC_CHECK_MEMBERS
1145 Check for given members in aggregates (e.g., pw_gecos in struct
1149 Checks if the compiler supports ISO C, included when needs special
1153 Checking whether the preprocessor indicates missing includes by the
1154 error code. stderr is checked by AC_TRY_CPP only as a fallback.
1157 Takes a language as argument and replaces AC_LANG_C,
1158 AC_LANG_CPLUSPLUS and AC_LANG_FORTRAN77.
1160 - AC_LANG_PUSH, AC_LANG_POP
1161 Are preferred to AC_LANG_SAVE, AC_LANG_RESTORE.
1164 - AC_FUNC_CHOWN, AC_FUNC_MALLOC, AC_FUNC_STRERROR_R,
1165 AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK, AC_FUNC_STAT, AC_FUNC_LSTAT,
1166 AC_FUNC_ERROR_AT_LINE, AC_FUNC_OBSTACK, AC_FUNC_STRTOD, AC_FUNC_FSEEKO.
1170 Sets GETGROUPS_LIBS.
1172 - AC_FUNC_GETLOADAVG
1173 Defines `HAVE_STRUCT_NLIST_N_UN_N_NAME' instead of `NLIST_NAME_UNION'.
1176 Now integrates `AC_DECL_YYTEXT' which is obsoleted.
1179 Arrange for large-file support.
1181 - AC_EXEEXT, AC_OBJEXT
1182 You are no longer expected to use them: their computation is
1183 performed by default.
1185 ** C++ compatibility
1186 Every macro has been revisited in order to support at best CC=c++.
1188 Major changes in Autoconf 2.14:
1189 There was no release of GNU Autoconf 2.14.
1191 Major changes in Autoconf 2.13:
1193 Released 1999-05-01 by Ben Elliston.
1195 * Support for building on Win32 systems where the only available C or
1196 C++ compiler is the Microsoft Visual C++ command line compiler
1197 (`cl'). Additional support for building on Win32 systems which are
1198 using the Cygwin or Mingw32 environments.
1199 * Support for alternative object file and executable file extensions.
1200 On Win32, for example, these are .obj and .exe. These are discovered
1201 using AC_OBJEXT and AC_EXEEXT, which substitute @OBJEXT@ and
1202 @EXEEXT@ in the output, respectively.
1203 * New macros: AC_CACHE_LOAD, AC_CACHE_SAVE, AC_FUNC_SELECT_ARGTYPES,
1204 AC_VALIDATE_CACHED_SYSTEM_TUPLE, AC_SEARCH_LIBS, AC_TRY_LINK_FUNC,
1205 AC_C_STRINGIZE, AC_CHECK_FILE(S), AC_PROG_F77 (and friends).
1206 * AC_DEFINE now has an optional third argument for a description to be
1207 placed in the config header input file (e.g. config.h.in).
1208 * The C++ code fragment compiled for the C++ compiler test had to be
1209 improved to include an explicit return type for main(). This was
1210 causing failures on systems using recent versions of the EGCS C++
1212 * Fixed an important bug in AC_CHECK_TYPE that would cause a configure
1213 script to report that `sometype_t' was present when only `type_t'
1215 * Merge of the FSF version of config.guess and config.sub to modernize
1216 these scripts. Add support for a few new hosts in config.guess.
1217 Incorporate latest versions of install-sh, mkinstalldirs and
1218 texinfo.tex from the FSF.
1219 * autoreconf is capable of running automake if necessary (and
1221 * Support for Fortran 77. See the Texinfo documentation for details.
1222 * Bug fixes and workarounds for quirky bugs in vendor utilities.
1224 Major changes in Autoconf 2.12:
1226 Released 1996-11-26 by David J. MacKenzie
1228 * AC_OUTPUT and AC_CONFIG_HEADER can create output files by
1229 concatenating multiple input files separated by colons, like so:
1230 AC_CONFIG_HEADER(config.h:conf.pre:config.h.in:conf.post)
1231 AC_OUTPUT(Makefile:Makefile.in:Makefile.rules)
1232 The arguments may be shell variables, to compute the lists on the fly.
1233 * AC_LINK_FILES and AC_CONFIG_SUBDIRS may be called multiple times.
1234 * New macro AC_OUTPUT_COMMANDS adds more commands to run in config.status.
1237 Major changes in Autoconf 2.11:
1239 Released November 18th, 1996, by David J. MacKenzie
1241 * AC_PROG_CC and AC_PROG_CXX check whether the compiler works.
1242 They also default CFLAGS/CXXFLAGS to "-g -O2" for gcc, instead of "-g -O".
1243 * AC_REPLACE_FUNCS defines HAVE_foo if the system has the function `foo'.
1244 * AC_CONFIG_HEADER expands shell variables in its argument.
1245 * New macros: AC_FUNC_FNMATCH, AC_FUNC_SETPGRP.
1246 * The "checking..." messages and the source code for test programs that
1247 fail are saved in config.log.
1248 * Another workaround has been added for seds with small command length limits.
1249 * config.sub and config.guess recognize more system types.
1252 Major changes in Autoconf 2.10:
1254 Released May 7th, 1996, by Roland McGrath
1257 * The cache variable names used by `AC_CHECK_LIB(LIB, FUNC, ...)' has
1258 changed: now $ac_cv_lib_LIB_FUNC, previously $ac_cv_lib_LIB.
1260 Major changes in Autoconf 2.9:
1262 Released March 16th, 1996, by Roland McGrath
1266 Major changes in Autoconf 2.8:
1268 Released March 8th, 1996, by Roland McGrath
1272 Major changes in Autoconf 2.7:
1274 Released November 22nd, 1995, by David J. MacKenzie
1278 Major changes in Autoconf 2.6:
1280 Released November 20th, 1995, by David J. MacKenzie
1284 Major changes in Autoconf 2.5:
1286 Released November 17th, 1995, by Roland McGrath
1288 * New configure options --bindir, --libdir, --datadir, etc., with
1289 corresponding output variables.
1290 * New macro: AC_CACHE_CHECK, to make using the cache easier.
1291 * config.log contains the command being run as well as any output from it.
1292 * AC_CHECK_LIB can check for libraries with "." or "/" or "+" in their name.
1293 * AC_PROG_INSTALL doesn't cache a name for install-sh, for sharing caches.
1294 * AC_CHECK_PROG, AC_PATH_PROG, AC_CHECK_PROGS, AC_PATH_PROGS, and
1295 AC_CHECK_TOOL can search a path other than $PATH.
1296 * AC_CHECK_SIZEOF takes an optional size to use when cross-compiling.
1298 Major changes in Autoconf 2.4:
1300 Released June 14th, 1995, by David J. MacKenzie
1302 * Fix a few bugs found by Emacs testers.
1304 Major changes in Autoconf 2.3:
1306 Released March 27th, 1995, by David J. MacKenzie
1308 * Fix the cleanup trap in several ways.
1309 * Handle C compilers that are picky about option placement.
1310 * ifnames gets the version number from the right directory.
1312 Major changes in Autoconf 2.2:
1314 Released March 8th, 1995, by David J. MacKenzie
1316 * The ifnames utility is much faster but requires a "new awk" interpreter.
1317 * AC_CHECK_LIB and AC_HAVE_LIBRARY check and add the new
1318 library before existing libs, not after, in case it uses them.
1319 * New macros: AC_FUNC_GETPGRP, AC_CHECK_TOOL.
1320 * Lots of bug fixes.
1321 * Many additions to the TODO file :-)
1323 Major changes in Autoconf 2.1:
1325 Released November 4th, 1994, by David J. MacKenzie
1328 * More explanations in the manual.
1329 * Fix a spurious failure in the testsuite.
1330 * Clarify some warning messages.
1331 * autoreconf by default only rebuilds configure and config.h.in files
1332 that are older than any of their particular input files; there is a
1333 --force option to use after installing a new version of Autoconf.
1335 Thanks to everybody who's submitted changes and additions to Autoconf!
1336 I've incorporated many of them, and am still considering others for
1337 future releases -- but I didn't want to postpone this release indefinitely.
1339 Caution: don't indiscriminately rebuild configure scripts with
1340 Autoconf version 2. Some configure.in files need minor adjustments to
1341 work with it; the documentation has a chapter on upgrading. A few
1342 configure.in files, including those for GNU Emacs and the GNU C
1343 Library, need major changes because they relied on undocumented
1344 internals of version 1. Future releases of those packages will have
1345 updated configure.in files.
1347 It's best to use GNU M4 1.3 (or later) with Autoconf version 2.
1348 Autoconf now makes heavy use of M4 diversions, which were implemented
1349 inefficiently in GNU M4 releases before 1.3.
1351 Major changes in Autoconf 2.0:
1353 Released October 26th, 1994, by David J. MacKenzie
1355 ** New copyright terms:
1356 * There are no restrictions on distribution or use of configure scripts.
1359 * Autoconf manual is reorganized to make information easier to find
1360 and has several new indexes.
1361 * INSTALL is reorganized and clearer and is now made from Texinfo source.
1364 * autoscan to generate a preliminary configure.in for a package by
1365 scanning its source code for commonly used nonportable functions,
1366 programs, and header files.
1367 * ifnames to list the symbols used in #if and #ifdef directives in a
1369 * autoupdate to update a configure.in to use the version 2 macro names.
1370 * autoreconf to recursively remake configure and configuration header
1371 files in a source tree.
1373 ** Changed utilities:
1374 * autoheader can take pieces of acconfig.h to replace config.h.{top,bot}.
1375 * autoconf and autoheader can look for package-local definition files
1376 in an alternate directory.
1379 * AC_CACHE_VAL to share results of tests between configure runs.
1380 * AC_DEFUN to define macros, automatically AC_PROVIDE them, and ensure
1381 that macros invoked with AC_REQUIRE don't interrupt other macros.
1382 * AC_CONFIG_AUX_DIR, AC_CANONICAL_SYSTEM, AC_CANONICAL_HOST, AC_LINK_FILES to
1383 support deciding unguessable features based on the host and target types.
1384 * AC_CONFIG_SUBDIRS to recursively configure a source tree.
1385 * AC_ARG_PROGRAM to use the options --program-prefix,
1386 --program-suffix, and --program-transform-name to change the names
1387 of programs being installed.
1388 * AC_PREFIX_DEFAULT to change the default installation prefix.
1389 * AC_TRY_COMPILE to compile a test program without linking it.
1390 * AC_CHECK_TYPE to check whether sys/types.h or stdlib.h defines a given type.
1391 * AC_CHECK_LIB to check for a particular function and library.
1392 * AC_MSG_CHECKING and AC_MSG_RESULT to print test results, on a single line,
1393 whether or not the test succeeds. They obsolete AC_CHECKING and AC_VERBOSE.
1394 * AC_SUBST_FILE to insert one file into another.
1395 * AC_FUNC_MEMCMP to check whether memcmp is 8-bit clean.
1396 * AC_FUNC_STRFTIME to find strftime even if it's in -lintl.
1397 * AC_FUNC_GETMNTENT to find getmntent even if it's in -lsun or -lseq.
1398 * AC_HEADER_SYS_WAIT to check whether sys/wait.h is POSIX.1 compatible.
1401 * Many macros renamed systematically, but old names are accepted for
1402 backward compatibility.
1403 * AC_OUTPUT adds the "automatically generated" comment to
1404 non-Makefiles where it finds @configure_input@ in an input file, to
1405 support files with various comment syntaxes.
1406 * AC_OUTPUT does not replace "prefix" and "exec_prefix" in generated
1407 files when they are not enclosed in @ signs.
1408 * AC_OUTPUT allows the optional environment variable CONFIG_STATUS to
1409 override the file name "config.status".
1410 * AC_OUTPUT takes an optional argument for passing variables from
1411 configure to config.status.
1412 * AC_OUTPUT and AC_CONFIG_HEADER allow you to override the input-file names.
1413 * AC_OUTPUT automatically substitutes the values of CFLAGS, CXXFLAGS,
1414 CPPFLAGS, and LDFLAGS from the environment.
1415 * AC_PROG_CC and AC_PROG_CXX now set CFLAGS and CXXFLAGS, respectively.
1416 * AC_PROG_INSTALL looks for install-sh or install.sh in the directory
1417 specified by AC_CONFIG_AUXDIR, or srcdir or srcdir/.. or
1418 srcdir/../.. by default.
1419 * AC_DEFINE, AC_DEFINE_UNQUOTED, and AC_SUBST are more robust and smaller.
1420 * AC_DEFINE no longer prints anything, because of the new result reporting
1421 mechanism (AC_MSG_CHECKING and AC_MSG_RESULT).
1422 * AC_VERBOSE pays attention to --quiet/--silent, not --verbose.
1423 * AC_ARG_ENABLE and AC_ARG_WITH support whitespace in the arguments to
1424 --enable- and --with- options.
1425 * AC_CHECK_FUNCS and AC_CHECK_HEADERS take optional shell commands to
1426 execute on success or failure.
1427 * Checking for C functions in C++ works.
1430 * AC_REMOTE_TAPE and AC_RSH removed; too specific to tar and cpio, and
1431 better maintained with them.
1432 * AC_ARG_ARRAY removed because no one was likely using it.
1433 * AC_HAVE_POUNDBANG replaced with AC_SYS_INTERPRETER, which doesn't
1434 take arguments, for consistency with all of the other specific checks.
1437 * Comes with config.sub and config.guess, and uses them optionally.
1438 * Uses config.cache to cache test results. An alternate cache file
1439 can be selected with the --cache-file=FILE option.
1440 * Uses optional shell scripts $prefix/share/config.site and
1441 $prefix/etc/config.site to perform site or system specific initializations.
1442 * configure saves compiler output to ./config.log for debugging.
1443 * New files autoconf.m4 and autoheader.m4 load the other Autoconf macros.
1444 * acsite.m4 is the new name for the system-wide aclocal.m4.
1445 * Has a DejaGnu test suite.
1447 Major changes in Autoconf 1.11:
1449 * AC_PROG_INSTALL calls install.sh with the -c option.
1450 * AC_SET_MAKE cleans up after itself.
1451 * AC_OUTPUT sets prefix and exec_prefix if they weren't set already.
1452 * AC_OUTPUT prevents shells from looking in PATH for config.status.
1454 Plus a few other bug fixes.
1456 Major changes in Autoconf 1.10:
1458 * autoheader uses config.h.bot if present, analogous to config.h.top.
1459 * AC_PROG_INSTALL looks for install.sh in srcdir or srcdir/.. and
1461 * AC_PROG_CXX looks for cxx as a C++ compiler.
1463 Plus several bugs fixed.
1465 Major changes in Autoconf 1.9:
1467 * AC_YYTEXT_POINTER replaces AC_DECLARE_YYTEXT.
1468 * AC_SIZEOF_TYPE generates the cpp symbol name automatically,
1469 and autoheader generates entries for those names automatically.
1470 * AC_FIND_X gets the result from xmkmf correctly.
1471 * AC_FIND_X assumes no X if --without-x was given.
1472 * AC_FIND_XTRA adds libraries to the variable X_EXTRA_LIBS.
1473 * AC_PROG_INSTALL finds OSF/1 installbsd.
1475 Major changes in Autoconf 1.8:
1478 * New macros AC_LANG_C, AC_LANG_CPLUSPLUS, AC_LANG_SAVE, AC_LANG_RESTORE,
1479 AC_PROG_CXX, AC_PROG_CXXCPP, AC_REQUIRE_CPP
1480 for checking both C++ and C features in one configure script.
1481 * New macros AC_CHECKING, AC_VERBOSE, AC_WARN, AC_ERROR for printing messages.
1482 * New macros AC_FIND_XTRA, AC_MMAP, AC_SIZEOF_TYPE, AC_PREREQ,
1483 AC_SET_MAKE, AC_ENABLE.
1486 * AC_FIND_X looks for X in more places.
1487 * AC_PROG_INSTALL defaults to install.sh instead of cp, if it's in srcdir.
1488 install.sh is distributed with Autoconf.
1489 * AC_DECLARE_YYTEXT has been removed because it can't work, pending
1490 a rewrite of quoting in AC_DEFINE.
1491 * AC_OUTPUT adds its comments in C format when substituting in C files.
1492 * AC_COMPILE_CHECK protects its ECHO-TEXT argument with double quotes.
1494 ** New or changed command line options:
1495 * configure accepts --enable-FEATURE[=ARG] and --disable-FEATURE options.
1496 * configure accepts --without-PACKAGE, which sets withval=no.
1497 * configure accepts --x-includes=DIR and --x-libraries=DIR.
1498 * Giving --with-PACKAGE no argument sets withval=yes instead of withval=1.
1499 * configure accepts --help, --version, --silent/--quiet, --no-create options.
1500 * configure accepts and ignores most other Cygnus configure options, and
1501 warns about unknown options.
1502 * config.status accepts --help, --version options.
1504 ** File names and other changes:
1505 * Relative srcdir values are not made absolute.
1506 * The values of @prefix@ and @exec_prefix@ and @top_srcdir@ get substituted.
1507 * Autoconf library files are installed in ${datadir}/autoconf, not ${datadir}.
1508 * autoheader optionally copies config.h.top to the beginning of config.h.in.
1509 * The example Makefile dependencies for configure et al. work better.
1510 * Namespace cleanup: all shell variables used internally by Autoconf
1511 have names beginning with `ac_'.
1513 More big improvements are in process for future releases, but have not
1514 yet been (variously) finished, integrated, tested, or documented enough
1517 Major changes in Autoconf 1.7:
1519 * New macro AC_OBSOLETE.
1520 * Bugs in Makefile.in fixed.
1521 * AC_LONG_FILE_NAMES improved.
1523 Major changes in Autoconf 1.6:
1525 * New macro AC_LONG_64_BITS.
1526 * Multiple .h files can be created.
1527 * AC_FIND_X looks for X files directly if it doesn't find xmkmf.
1528 * AC_ALLOCA defines C_ALLOCA if using alloca.c.
1529 * --with-NAME can take a value, e.g., --with-targets=sun4,hp300bsd.
1530 * Unused --no-create option to configure removed.
1531 * autoheader doesn't change the timestamp of its output file if
1532 the file didn't change.
1533 * All macros that look for libraries now use AC_HAVE_LIBRARY.
1534 * config.status checks three optional environment variables to
1535 modify its behavior.
1536 * The usual bug fixes.
1538 Major changes in Autoconf 1.5:
1540 * New macros AC_FIND_X, AC_OFF_T, AC_STAT_MACROS_BROKEN, AC_REVISION.
1541 * autoconf and autoheader scripts have GNU standards conforming
1542 --version and --help options (they print their message and exit).
1545 Major changes in Autoconf 1.4:
1547 * New macros AC_HAVE_POUNDBANG, AC_TIME_WITH_SYS_TIME, AC_LONG_DOUBLE,
1548 AC_GETGROUPS_T, AC_DEFINE_UNQUOTED.
1549 * autoconf and autoheader use the M4 environment variable to determine the
1550 name of the M4 program to use.
1551 * The --macrodir option to autoconf and autoheader specifies the directory
1552 in which acspecific.m4, acgeneral.m4, etc. reside if not the default.
1553 * autoconf and autoheader can take `-' as their file names, which means to
1554 read stdin as input.
1555 * Resulting configure scripts can take a --verbose option which causes them
1556 to print the results of their tests.
1557 * AC_DEFINE quotes its second argument in such a way that spaces, magic
1558 shell characters, etc. will be preserved during various stages of
1559 expansion done by the shell. If you don't want this, use
1560 AC_DEFINE_UNQUOTED instead.
1561 * Much textual processing done with external calls to tr and sed have been
1562 internalized with builtin M4 `patsubst' and `translit' calls.
1563 * AC_OUTPUT doesn't hardwire the file names it outputs. Instead, you can
1564 set the shell variables `gen_files' and `gen_config' to the list of
1565 file names to output.
1566 * AC_DECLARE_YYTEXT does an AC_SUBST of `LEX_OUTPUT_ROOT', which may be
1567 "lex.yy" or "lexyy", depending on the system.
1568 * AC_PROGRAMS_CHECK takes an optional third arg. If given, it is used as
1570 * If AC_ALLOCA chooses alloca.c, it also defines STACK_DIRECTION.
1571 * AC_CONST works much more reliably on more systems.
1574 Major changes in Autoconf 1.3:
1576 configure no longer requires awk for packages that use a config.h.
1577 Support handling --with-PACKAGE options.
1578 New `autoheader' script to create `config.h.in' from `configure.in'.
1579 Ignore troublesome -lucb and -lPW when searching for alloca.
1580 Rename --exec_prefix to --exec-prefix for GNU standards conformance.
1581 Improve detection of STDC library.
1582 Add AC_HAVE_LIBRARY to check for non-default libraries.
1583 Function checking should work with future GNU libc releases.
1585 Major changes in Autoconf 1.2:
1587 The --srcdir option is now usually unnecessary.
1588 Add a file containing sample comments describing CPP macros.
1589 A comment in config.status tells which host it was configured on.
1590 Substituted variable values can now contain commas.
1591 Fix bugs in various feature checks.
1593 Major changes in Autoconf 1.1:
1595 Added AC_STRCOLL macro.
1596 Made AC_GETLOADAVG check for more things.
1597 AC_OUTPUT argument is now optional.
1602 Copyright (C) 1993, 1994, 1995, 1996, 1998, 1999, 2000, 2001, 2002,
1603 2003, 2004, 2005, 2006, 2007 Free Software Foundation, Inc.
1605 This program is free software: you can redistribute it and/or modify
1606 it under the terms of the GNU General Public License as published by
1607 the Free Software Foundation, either version 3 of the License, or
1608 (at your option) any later version.
1610 This program is distributed in the hope that it will be useful,
1611 but WITHOUT ANY WARRANTY; without even the implied warranty of
1612 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
1613 GNU General Public License for more details.
1615 You should have received a copy of the GNU General Public License
1616 along with this program. If not, see <http://www.gnu.org/licenses/>.