1 GNU Autoconf NEWS - User visible changes.
3 * Major changes in Autoconf 2.64a (????-??-??) [experimental]
6 ** The following undocumented autoconf macros, removed in Autoconf 2.64,
10 These macros are present only for backwards compatibility purposes.
12 ** The AC_FC_FREEFORM macro no longer suffers from a whitespace bug that
13 made it fail with some Fortran compilers (regression introduced in
16 ** The following documented autotest macros are new:
19 * Major changes in Autoconf 2.64 (2009-07-26) [stable]
20 Released by Eric Blake, based on git versions 2.63b.*.
22 ** Autoconf now requires GNU M4 1.4.6 or later. Earlier versions of M4
23 have a bug in regular expression handling that interferes with some
24 of the speedups provided since Autoconf 2.63. GNU M4 1.4.13 or
27 ** AS_IF and AS_CASE have been taught to avoid syntax errors even when
28 given arguments that expand to just whitespace.
30 ** The following documented autoconf macros are new:
31 AC_ERLANG_SUBST_ERTS_VER
33 ** The autoheader tool now understands m4 macro arguments passed to
34 AC_DEFINE and AC_DEFINE_UNQUOTED.
36 ** Ensure AT_CHECK can support commands that include a # given with
37 proper m4 quoting. For shell comments, this is a new feature; for
38 non-shell comments, this fixes a regression introduced in 2.63b.
39 Additionally, AT_CHECK correctly supplies shell escapes for
40 metacharacters occurring in m4 macro expansions within the expected
41 stdout and stderr parameters.
43 ** The macro AT_CHECK now understands the concept of hard failure. If
44 a test exits with an unexpected status 99, cleanup actions for the
45 test are inhibited and the test is treated as a failure regardless
46 of AT_XFAIL_IF. It also understands the new directives
47 ignore-nolog, stdout-nolog, and stderr-nolog.
49 ** The following documented autotest macros are new:
50 AT_CHECK_UNQUOTED AT_FAIL_IF AT_SKIP_IF
52 ** The following documented m4sugar macros are new:
53 m4_argn m4_copy_force m4_default_nblank m4_default_nblank_quoted
54 m4_ifblank m4_ifnblank m4_rename_force
56 ** The autoconf testsuite now exercises all Erlang macros.
58 * Major changes in Autoconf 2.63b (2009-03-31) [beta]
59 Released by Eric Blake, based on git versions 2.63.*.
61 ** The manual is now shipped under the terms of the GNU FDL 1.3.
63 ** AC_REQUIRE now detects the case of an outer macro which first expands
64 then later indirectly requires the same inner macro. Previously,
65 this case led to silent out-of-order expansion (bug present since
66 2.50); it now issues a syntax warning, and duplicates the expansion
67 of the inner macro to guarantee dependencies have been met. See
68 the manual for advice on how to refactor macros in order to avoid
69 the bug in earlier autoconf versions and avoid increased script
70 size in the current version.
72 ** AC_DEFUN_ONCE has improved semantics. Previously, a macro declared
73 with AC_DEFUN_ONCE warned on a second invocation; and out-of-order
74 expansion was still possible. Now, dependencies are guaranteed,
75 and subsequent invocations are a silent no-op. This makes
76 AC_DEFUN_ONCE an ideal macro for silencing AC_REQUIRE warnings.
78 ** The following macros are now defined with AC_DEFUN_ONCE. This means
79 a subtle change in semantics; previously, an AC_DEFUN macro could
80 expand one of these macros multiple times or surround the macro
81 inside shell conditional text to bypass the effects of these
82 macros, but now the macro will expand exactly once, and prior to
83 the start of any enclosing AC_DEFUN macro:
84 AC_CANONICAL_BUILD AC_CANONICAL_HOST AC_CANONICAL_TARGET
85 AC_HEADER_ASSERT AC_PROG_INSTALL AC_PROG_MKDIR_P
86 AC_USE_SYSTEM_EXTENSIONS
88 ** AC_LANG_ERLANG works once again (regression introduced in 2.61a).
90 ** AC_HEADER_ASSERT is fixed so that './configure --enable-assert' no
91 longer mistakenly disables assertions.
93 ** AC_INIT now takes an optional fifth parameter that can be used to
94 set AC_PACKAGE_URL, a URL for the package's home page; the URL is
95 used in `configure --help' and is also available via AC_DEFINE.
97 ** Autotest testsuites accept an option --jobs[=N] for parallel testing.
98 This feature is still in testing, and may not work on every
99 platform, help in improving it would be appreciated.
101 ** Autotest testsuites do not attempt to write startup error messages
102 to the log file before that is opened (regression introduced in 2.63).
104 ** Configure scripts now use shell functions. This feature leads to
105 smaller configure files and faster execution.
107 ** Present But Cannot Be Compiled: Autoconf will now proceed with
108 the compiler's result if a header is present but cannot be compiled.
109 The warning is still printed, and you should really fix it by
110 providing a fourth parameter to AC_CHECK_HEADER/AC_CHECK_HEADERS.
112 ** Autoreconf added aclocal to the set of programs affected by the
113 `autoreconf -I dir' option.
115 ** The following documented m4sugar macros are new:
116 m4_chomp m4_chomp_all m4_cleardivert m4_curry m4_default_quoted
117 m4_esyscmd_s m4_map_args m4_map_args_pair m4_map_args_sep
118 m4_map_args_w m4_set_map m4_set_map_sep m4_stack_foreach
119 m4_stack_foreach_lifo m4_stack_foreach_sep
120 m4_stack_foreach_sep_lifo
122 ** The following m4sugar macros are documented now, but in some cases
123 with slightly different semantics than what the previous
124 undocumented version had:
125 m4_copy m4_dumpdefs m4_rename m4_version_prereq
127 ** The m4sugar macro m4_expand has been taught to handle unterminated
128 comments and shell case statements. As a result, it is used
129 internally in more places, such as AC_DEFINE and AT_CHECK. Most
130 uses of AC_DEFINE and AT_CHECK should not behave any differently;
131 however, it may be necessary to add double-quoting around
132 unbalanced `(' where single-quoting used to be sufficient.
134 ** The following documented m4sh macros are new:
135 AS_INIT_GENERATED AS_LINENO_PREPARE AS_ME_PREPARE AS_SET_STATUS
136 AS_VAR_APPEND AS_VAR_ARITH AS_VAR_COPY
138 ** The following m4sh macros are documented now, but in some cases
139 with slightly different semantics than what the previous
140 undocumented version had:
141 AS_ECHO AS_ECHO_N AS_ESCAPE AS_EXIT AS_LITERAL_IF AS_UNSET
142 AS_VAR_IF AS_VAR_POPDEF AS_VAR_PUSHDEF AS_VAR_SET AS_VAR_SET_IF
143 AS_VAR_TEST_SET AS_VERSION_COMPARE
145 ** The m4sh macros AS_IF and AS_CASE can now be used in shell lists.
146 The responsibility for supplying a trailing newline now belongs to
147 the call site, but since most users did not add dnl, this generally
148 results in fewer empty lines in configure.
151 * Major changes in Autoconf 2.63 (2008-09-09) [stable]
152 Released by Eric Blake, based on git versions 2.62.*.
154 ** AC_C_BIGENDIAN does not mistakenly report "universal" for some
155 bigendian hosts, a regression introduced with universal binary
158 ** AC_PATH_X now includes /lib64 and /usr/lib64 in its list of default
161 ** AC_USE_SYSTEM_EXTENSIONS no longer conflicts with an external
162 AC_DEFINE([__EXTENSIONS__]). This fixes a regression introduced in
163 2.62 when using macros such as AC_AIX that were made obsolete in
164 favor of the more portable AC_USE_SYSTEM_EXTENSIONS.
166 ** AC_CHECK_TARGET_TOOLS is usable in the non-cross-compile case.
168 ** Newly obsolete macros
169 The following macro has been marked obsolete, since current porting
170 targets can safely assume C89 semantics that signal handlers return
171 void. We have no current plans to remove the macro.
175 ** The macros m4_map and m4_map_sep now ignore any list elements
176 consisting of just empty quotes, and m4_map_sep now expands its
177 separator. This fixes a regression in 2.62 when these macros were
178 first documented, for the sake of clients expecting the semantics
179 that these macros had prior to that time. The new macros m4_mapall
180 and m4_mapall_sep, along with extra quoting of the separator, can
181 be used to get the semantics that m4_map_sep had in 2.62.
183 ** Clients of m4_expand, such as AS_HELP_STRING and AT_SETUP, can now
184 handle properly quoted but otherwise unbalanced parentheses (for
185 some macros, this fixes a regression in 2.62).
187 ** Two new quadrigraphs have been introduced: @{:@ for (, and @:}@ for ),
188 allowing the output of unbalanced parentheses in more contexts.
190 ** The following m4sugar macros are new:
191 m4_cleardivert m4_joinall m4_mapall m4_mapall_sep m4_reverse
192 m4_set_add m4_set_add_all m4_set_contains m4_set_contents
193 m4_set_delete m4_set_difference m4_set_dump m4_set_empty
194 m4_set_foreach m4_set_intersection m4_set_list m4_set_listc
195 m4_set_remove m4_set_size m4_set_union
197 ** The following m4sugar macros now accept multiple arguments, as is the
198 case with underlying m4:
199 m4_defn m4_popdef m4_undefine
201 ** The following m4sugar macros now guarantee linear scaling; they
202 previously had linear scaling with m4 1.6 but quadratic scaling
203 when using m4 1.4.x. All macros built on top of these also gain
204 the scaling improvements.
205 m4_bmatch m4_bpatsubsts m4_case m4_cond m4_do m4_dquote_elt
206 m4_foreach m4_join m4_list_cmp m4_map m4_map_sep m4_max
209 ** AT_KEYWORDS once again performs expansion on its argument, such that
210 AT_KEYWORDS([m4_if([$1], [], [default])]) no longer complains about
211 the possibly unexpanded m4_if [regression introduced in 2.62].
213 ** Config header templates `#undef UNDEFINED /* comment */' do not lead to
214 nested comments any more; regression introduced in 2.62.
217 * Major changes in Autoconf 2.62 (2008-04-05) [stable]
218 Released by Eric Blake, based on git versions 2.61a.*.
220 ** Many optimizations have been applied to make overall execution faster.
222 ** Autotest now makes use of shell functions.
224 ** config.status now uses awk instead of sed also for config headers.
226 - As a side effect, AC_DEFINE and AC_DEFINE_UNQUOTED now handle multi-line
227 values, i.e., backslash-newline combinations are handled correctly.
228 Further, for config headers, the total size of values is not limited by
229 the POSIX length limit of text lines any more, only each single line.
231 ** New config variable `top_build_prefix'.
233 ** New Autoconf macros:
234 AC_AUTOCONF_VERSION AC_OPENMP AC_PATH_PROGS_FEATURE_CHECK
236 ** AC_C_BIGENDIAN now supports universal binaries a la Mac OS X.
238 ** AC_C_RESTRICT now prefers to #define 'restrict' to a variant spelling
239 like '__restrict' if the variant spelling is available, as this is
240 more likely to work when mixing C and C++ code.
242 ** AC_CHECK_ALIGNOF's type argument T is now documented better: it must
243 be a string of tokens such that "T y;" is a valid member declaration
246 ** AC_CHECK_SIZEOF now accepts objects as well as types: the general rule
247 is that sizeof (X) works, then AC_CHECK_SIZEOF (X) should work.
249 ** AC_CHECK_TYPE and AC_CHECK_TYPES now work on any C type-name; formerly,
250 they did not work for function types. In C++, they now work on any
251 type-id that can be the operand of sizeof; this is similar to C,
252 except it excludes anonymous struct and union types. Formerly,
253 some (but not all) C++ types involving anonymous struct and union
254 were accepted, though this was not documented.
256 ** AC_CONFIG_LINKS now prefers to link against files in the build tree
257 if found, and it works to link against a file of the same name in
258 the source tree, even if both trees coincide.
260 ** AC_INIT no longer alters $@; regression introduced in 2.60.
262 ** AC_USE_SYSTEM_EXTENSIONS now defines _ALL_SOURCE for Interix platforms.
264 ** AS_HELP_STRING no longer underquotes its first argument; it also handles
265 the case where the first argument contains single-quoted commas.
266 For example, "AS_HELP_STRING([-a, [--arg[=foo]]], [bar])" produces:
267 " -a, --arg[=foo] bar"
268 Additionally, the macro now takes two additional arguments,
269 indent-column and wrap-column; these should not normally be needed,
270 but can be used to fine-tune how the output text is wrapped.
272 ** AC_PROG_INSTALL now requires an install program that can install multiple
273 files into a target directory.
275 ** The command 'autoconf -' now correctly processes a file from stdin.
277 ** 'autoreconf -m' now honors $MAKE.
279 ** For all of the directory arguments for 'configure', such as '--prefix'
280 or '--bindir', trailing slashes are stripped. As an example, if
281 tab completion in the user's shell appends trailing slashes, the
282 command './configure --prefix=/usr/' will still result in an
283 expanded libdir value of /usr/lib, not /usr//lib.
285 ** `configure --help=recursive' now works in read-only trees and from
286 unconfigured build trees.
288 ** If precious variables differ only in whitespace, then the cache consistency
289 check warns instead of fails, and reuses the old value.
291 ** AT_BANNER is now documented.
293 ** AT_SETUP now handles macro expansions properly when calculating line
296 ** Autotest now determines $srcdir correctly.
298 ** Testsuites built by autotest now accept a -C/--directory=DIR option
299 to adjust the working directory prior to creating files.
301 ** Autoconf now requires GNU M4 1.4.5 or later. Earlier versions of M4 have
302 a bug in macro tracing that interferes with the interaction between
303 Autoconf and Automake. GNU M4 1.4.11 or later is recommended. The
304 configure search for a working M4 is improved.
306 ** For portability with the eventual M4 2.0, macros should no longer use
307 anything larger than $9 to refer to arguments.
309 ** Documentation for m4sugar is improved.
311 - The following macros were previously available as undocumented
312 interfaces; the macros are now documented as stable interfaces.
314 __oline__ m4_assert m4_bmatch m4_bpatsubsts m4_car m4_case
315 m4_cdr m4_default m4_divert_once m4_divert_pop m4_divert_push
316 m4_divert_text m4_do m4_errprintn m4_fatal m4_flatten
317 m4_ifndef m4_ifset m4_ifval m4_ifvaln m4_location
318 m4_n m4_shiftn m4_strip m4_warn
320 - The following macros were previously available as undocumented
321 interfaces, but had bug fixes or semantic changes as part of this
322 release. Packages that relied on the undocumented behavior
323 should be analyzed to make sure they will still work with the
324 new documented behavior.
326 m4_cmp m4_list_cmp m4_join m4_map m4_map_sep m4_sign
327 m4_text_box m4_text_wrap m4_version_compare
329 - The m4_wrap macro used to have unspecified order, but now
330 guarantees FIFO order. m4_wrap_lifo was added to guarantee LIFO
333 - Packages using the undocumented m4sugar macro m4_PACKAGE_VERSION
334 should consider using the new AC_AUTOCONF_VERSION instead.
336 - m4sugar macros that are not documented in the manual are still
337 deemed experimental, and should not be used outside of Autoconf.
339 ** The m4sugar macros m4_append and m4_append_uniq, first documented in
340 2.60, have been fixed to treat both the string and the separator
341 arguments consistently with regards to quoting. Prior to this fix,
342 m4_append_uniq could mistakenly duplicate entries if the expansion
343 of the separator resulted in a different string (for example, if it
344 contained quotes, a comma, or a macro name). However, it means
345 that programs previously using
346 m4_append([name], [string], [[, ]])
347 are now using a four-character separator instead of the intended
348 comma and space. If you need portability to earlier versions of
349 Autoconf, you can insert the following snippet after AC_INIT but
350 before any other macro expansions, to enforce the new semantics:
351 m4_pushdef([m4_append], [m4_define([$1],
352 m4_ifdef([$1], [m4_defn([$1])[$3]])[$2])])
353 Additionally, m4_append_uniq now takes optional parameters that can
354 be used to take action depending on whether anything was appended,
355 and warns if a non-empty separator occurs within the string being
356 appended, since that can lead to duplicates.
358 ** The following m4sugar macros are new:
359 m4_append_uniq_w m4_apply m4_combine m4_cond m4_count
360 m4_dquote_elt m4_echo m4_expand m4_ignore m4_make_list m4_max
361 m4_min m4_newline m4_shift2 m4_shift3 m4_unquote m4_wrap_lifo
363 ** Warnings are now generated by default when an installer invokes
364 'configure' with an unknown --enable-* or --with-* option.
365 These warnings can be disabled with the new AC_DISABLE_OPTION_CHECKING
366 macro, or by invoking 'configure' with --disable-option-checking.
368 ** Existing obsolete macros
369 The documentation for the following macros is adjusted to make it
370 more clear that they have previously been marked obsolete, as their
371 functionality can be accomplished by other macros. We have no
372 current plans to remove them from Autoconf.
374 AC_ENABLE AC_STRUCT_ST_BLKSIZE AC_STRUCT_ST_RDEV AC_WITH
376 ** Newly obsolete macros
377 The following macros have been marked obsolete, as they only
378 perform a subset of AC_USE_SYSTEM_EXTENSIONS. We have no current
379 plans to remove them.
381 AC_AIX AC_GNU_SOURCE AC_ISC_POSIX AC_MINIX
383 ** AC_C_LONG_DOUBLE is obsolescent.
384 The documentation now says that AC_C_LONG_DOUBLE is obsolescent: it
385 tests for problems that are so old that it is no longer of
386 practical importance on current systems. New programs need not use
387 AC_C_LONG_DOUBLE. We have no current plans to remove it.
389 ** AC_DIAGNOSE, AC_WARNING, and AC_FATAL are obsolescent.
390 The documentation now favors the use of M4sugar macros m4_warn and
391 m4_fatal, since the naming makes it more obvious that the
392 diagnostics are associated with M4 expansion (ie. when running
393 `autoconf'), and offers less confusion with the AC_MSG_ERROR,
394 AC_MSG_FAILURE, and AC_MSG_WARN macros which manage diagnostics
395 when running `configure'. We have no current plans to remove these
399 * Major changes in Autoconf 2.61a (2006-12-11)
401 ** AC_FUNC_FSEEKO was broken in 2.61; it didn't make fseeko and ftello visible
402 on many platforms. This has been fixed.
404 ** AC_FUNC_SETVBUF_REVERSED is now obsolete. It is still defined for backward
405 compatibility but it does nothing. The macro was already
406 obsolescent, as the last systems to have the problem were those
407 based on SVR2, which became obsolete in 1987. The macro had bugs
408 on some modern systems and could no longer be maintained reliably
409 due to lack of ancient systems to test it on.
411 ** config.status now uses awk instead of sed for most substitutions, for speed.
413 - As a side effect multi-line values of substituted variables no
414 longer have a small limit in total size, though for portability
415 each line should not exceed the POSIX length limit for text lines.
417 - It is now documented that Makefile.in should not contain
418 overlapping variable occurrences, e.g., @VAR1@VAR2@.
419 Autoconf's behavior was always iffy in such cases, and the
420 awk implementation has changed the behavior.
422 ** Many uses of 'echo' have been rewritten so that Autoconf-generated
423 scripts have fewer problems with strings or file names containing
424 embedded special characters such as backslash or leading "-". This
425 was implemented by using `printf '%s\n' "$foo"' instead of `echo
426 "$foo"' when printf works. Due to the implementation technique
427 used, Autoconf-generated scripts now run considerably more slowly
428 on ancient implementations lacking printf. However, this should
429 not be a problem, since Autoconf-generated scripts in practice
430 invariably find a more-modern shell these days.
433 * Major changes in Autoconf 2.61 (2006-11-17)
435 ** New macros AC_C_FLEXIBLE_ARRAY_MEMBER, AC_C_VARARRAYS.
437 ** AC_ARG_ENABLE and AC_ARG_WITH now allow '.' in feature and package names.
440 * Major changes in Autoconf 2.60b (2006-10-22)
443 Autoconf-generated shell scripts no longer export BIN_SH, due to
444 configuration hassles with this. Installers who need BIN_SH in
445 their environment should set it before invoking 'configure' and
446 'make'. As far as we know, this affects only Unixware installations.
448 ** Obsolescent macros
449 The documentation now says that the following macros are obsolescent,
450 as they are superseded by Gnulib:
452 AC_FUNC_FNMATCH AC_FUNC_FNMATCH_GNU AC_FUNC_GETLOADVG AC_REPLACE_FNMATCH
454 New programs should use the Gnulib counterparts of these macros.
455 We have no current plans to remove them from Autoconf.
457 ** AC_COMPUTE_INT no longer caches or reports results.
459 ** AC_CHECK_DECL now also works with aggregate objects.
461 ** AC_USE_SYSTEM_EXTENSIONS now defines _TANDEM_SOURCE for NonStop platforms.
463 ** GNU M4 1.4.7 or later is now recommended.
466 New M4sugar macro, which is more secure than the POSIX M4 maketemp.
469 Now an alias for m4_mkstemp.
471 * Major changes in Autoconf 2.60a (2006-08-25)
473 ** GNU M4 1.4.6 or later is now recommended.
475 ** The check for C99 now tests for varargs macros, as documented.
476 It also tests that the preprocessor supports 64-bit integers.
478 ** Autoconf now uses constructs like "#ifdef HAVE_STDLIB_H" rather than
479 "#if HAVE_STDLIB_H", so that it now works with "gcc -Wundef -Werror".
481 ** The functionality of the undocumented _AC_COMPUTE_INT is now provided
482 by a public and documented macro, AC_COMPUTE_INT. The parameters to the
483 two macros are different, so autoupdate will not change the old private name
484 to the new one. _AC_COMPUTE_INT may be removed in a future release.
486 ** AC_TYPE_LONG_LONG_INT and AC_TYPE_UNSIGNED_LONG_LONG_INT now require
487 that long long types be at least 64 bits wide, as C99 and tradition
488 requires. Formerly, they accepted implementations of any width.
491 * Major changes in Autoconf 2.60
493 Released 2006-06-23, by Ralf Wildenhues.
495 ** Autoconf no longer depends on whether m4wrap is FIFO (as Posix requires)
496 or LIFO (as in GNU M4 1.4.x). GNU M4 2.0 is expected to conform to Posix
497 here, so m4wrap/m4_wrap users should no longer depend on LIFO behavior.
499 ** Provide a way to turn off warnings about the changed directory variables.
501 * Major changes in Autoconf 2.59d
503 Released 2006-06-05, by Ralf Wildenhues.
505 ** GNU make now recommended for VPATH builds
506 INSTALL now suggests VPATH builds (e.g., "sh ../srcdir/configure")
507 only if you use GNU make. In practice, other 'make' implementations
508 have too many subtle incompatibilities in their support for VPATH.
509 Many packages (including Autoconf itself) are portable to other
510 'make' implementations, but some packages are not, and recommending
511 GNU make keeps the installation instructions simpler.
513 ** Even more safety checks for the new Directory variables:
514 Warn about suspicious `${datarootdir}' found in config files output.
516 ** AC_TRY_COMMAND, AC_TRY_EVAL, ac_config_guess, ac_config_sub, ac_configure
517 These never-documented macros and variables have been marked with
518 comments saying that they may be removed in a future release,
519 because their use can lead to unintended code being executed.
520 If you need functionality that only these macros or variables
521 currently supply, please write bug-autoconf@gnu.org.
523 ** AC_SUBST, AC_DEFINE
524 Literal arguments to these are passed to m4_pattern_allow now.
527 Passing 'ac_cv_prog_cc_stdc=no' to 'configure' now sets ac_cv_prog_cc_c99
528 and ac_cv_prog_cc_c89 to 'no' as well, for backward compatibility with
529 obsolete K&R tests in the Automake test suite.
538 Now more robust with special characters in file names, or when
539 multiple processes create the same directory at the same time.
541 ** Obsolescent macros
542 The documentation now says that the following macros are obsolescent:
543 they test for problems that are so old that they are no longer of
544 practical importance on current systems.
546 AC_C_BACKSLASH_A AC_FUNC_MEMCMP AC_HEADER_DIRENT
547 AC_C_CONST AC_FUNC_SELECT_ARGTYPES AC_HEADER_STAT
548 AC_C_PROTOTYPES AC_FUNC_SETPGRP AC_HEADER_STDC
549 AC_C_STRINGIZE AC_FUNC_SETVBUF_REVERSED AC_HEADER_SYS_WAIT
550 AC_C_VOLATILE AC_FUNC_STAT AC_HEADER_TIME
551 AC_FUNC_CLOSEDIR_VOID AC_FUNC_STRFTIME AC_ISC_POSIX
552 AC_FUNC_GETPGRP AC_FUNC_UTIME_NULL AC_PROG_GCC_TRADITIONAL
553 AC_FUNC_LSTAT AC_FUNC_VPRINTF AC_STRUCT_TM
555 New programs need not use these macros. We have no current plans to
559 For compatibility with future Libtool 2.0, autoreconf will invoke
560 libtoolize with the option `--ltdl' now, if LT_CONFIG_LTDL_DIR is
563 * Major changes in Autoconf 2.59c
565 Released 2006-04-12, by Ralf Wildenhues.
567 ** The configure command now redirects standard input from /dev/null,
568 to help avoid problems with subsidiary commands that might mistakenly
569 read standard input. AS_ORIGINAL_STDIN_FD points to the original
570 standard input before this redirection, if you really want configure to
571 read from standard input.
573 ** Directory variables adjusted to recent changes in the GNU Coding Standards.
574 The following directory variables are new:
576 datarootdir read-only architecture-independent data root [PREFIX/share]
577 localedir locale-specific message catalogs [DATAROOTDIR/locale]
578 docdir documentation root [DATAROOTDIR/doc/PACKAGE]
579 htmldir html documentation [DOCDIR]
580 dvidir dvi documentation [DOCDIR]
581 pdfdir pdf documentation [DOCDIR]
582 psdir ps documentation [DOCDIR]
584 The following variables have new default values:
586 datadir read-only architecture-independent data [DATAROOTDIR]
587 infodir info documentation [DATAROOTDIR/info]
588 mandir man documentation [DATAROOTDIR/man]
590 This means that if you use any of `@datadir@', `@infodir@', or
591 `@mandir@' in a file, you will have to ensure `${datarootdir}' is
592 defined in this file. As a temporary measure, if any of those are
593 found but no mention of `datarootdir', the substitutions will be
594 replaced with values that do not contain `${datarootdir}', and a
595 warning will be issued.
597 ** @top_builddir@ is now a dir name: it is always nonempty and doesn't have
598 a trailing slash. Similar change will be made to ac_top_builddir in a
599 future release; the old style value, which matches (../)*, is (and will
600 continue to be) available as ac_top_build_prefix.
603 New macro to check for support of 'typeof' syntax a la GNU C.
605 ** AC_CHECK_DECLS_ONCE, AC_CHECK_FUNCS_ONCE, AC_CHECK_HEADERS_ONCE
606 New "once-only" variants of commonly-used macros, to make 'configure'
607 smaller and faster in common cases.
610 New macro to check for strtold with C99 semantics.
613 New macro that lets builder disable assertions at 'configure'-time.
616 Now checks for X11/Xlib.h and XrmInitialize (X proper) rather than
617 X11/Intrinsic.h and XtMalloc (Xt).
619 ** AC_PRESERVE_HELP_ORDER
620 New macro that causes `configure' to display help strings for AC_ARG_ENABLE
621 and AC_ARG_WITH arguments in one region, in the order defined. The default
622 behavior is to group options of each classes separately.
624 ** AC_PROG_CC, AC_PROG_CXX
625 No longer automatically arrange to declare the 'exit' function of C,
626 when a C++ compiler is used. Standard Autoconf macros no longer use
627 'exit', so this is no longer an issue for them. If you use C++, and
628 want to call 'exit', you'll have to arrange for its declaration
629 yourself. But we now suggest you return from 'main' instead.
631 ** AC_PROG_CC_C89, AC_PROG_CC_C99
632 New macros for ISO C99 support. AC_PROG_CC_C89 and AC_PROG_CC_C99
633 check for ANSI C89 and ISO C99 support respectively.
636 Has been unobsoleted, and will check if the compiler supports ISO
637 C99, falling back to ANSI C89 if not. ac_cv_prog_cc_stdc is
638 retained for backwards compatibility, assuming the value of
639 ac_cv_prog_cc_c99 or ac_cv_prog_cc_c89 (whichever is valid, in
642 ** AC_STRUCT_DIRENT_D_INO, AC_STRUCT_DIRENT_D_TYPE
643 New macros for checking commonly-used members of struct dirent.
646 The substituted value can now contain newlines.
649 The substitution now occurs only when @variable@ is on a line by itself,
650 optionally surrounded by spaces and tabs. The whole line is replaced.
652 ** AC_TYPE_LONG_DOUBLE, AC_TYPE_LONG_DOUBLE_WIDER
653 New macros to check for long double, and whether it is wider than double.
654 The old macro AC_C_TYPE_LONG_DOUBLE has been marked as obsolete;
655 applications should switch to the new macro.
657 ** AC_TYPE_INT8_T, AC_TYPE_INT16_T, AC_TYPE_INT32_T, AC_TYPE_INT64_T,
658 AC_TYPE_INTMAX_T, AC_TYPE_INTPTR_T, AC_TYPE_LONG_LONG_INT, AC_TYPE_SSIZE_T,
659 AC_TYPE_UINT8_T, AC_TYPE_UINT16_T, AC_TYPE_UINT32_T, AC_TYPE_UINT64_T,
660 AC_TYPE_UINTMAX_T, AC_TYPE_UINTPTR_T, AC_TYPE_UNSIGNED_LONG_LONG_INT
661 New macros to check for C99 and POSIX types.
663 ** AC_USE_SYSTEM_EXTENSIONS
664 New macro to enable extensions to Posix.
667 New macro which is defined to the name of the first declared config header
668 or undefined if no config headers have been declared yet.
671 The macro correctly handles quadrigraphs now.
673 ** AS_BOURNE_COMPATIBLE, AS_SHELL_SANITIZE, AS_CASE
674 These macros are new or published now.
677 New macro for copyright notices in testsuite files.
679 ** ALLOCA, LIBOBJS, LTLIBOBJS
680 Object names added to these variables are now prefixed with `${LIBOBJDIR}',
681 as in `${LIBOBJDIR}alloca.o'. LIBOBJDIR is meant to be defined from
682 `Makefile.in' in case the object files lie in a different directory.
683 The LIBOBJDIR feature is experimental.
686 Supports --no-recursive now.
688 ** New macros to support Erlang/OTP.
689 New macros for configuring paths to Erlang tools and libraries:
690 AC_ERLANG_PATH_ERLC, AC_ERLANG_NEED_ERLC, AC_ERLANG_PATH_ERL,
691 AC_ERLANG_NEED_ERL, AC_ERLANG_CHECK_LIB, AC_ERLANG_SUBST_ROOT_DIR,
692 AC_ERLANG_SUBST_LIB_DIR.
694 New macros for configuring installation of Erlang libraries:
695 AC_ERLANG_SUBST_INSTALL_LIB_DIR, AC_ERLANG_SUBST_INSTALL_LIB_SUBDIR.
697 ** The manual now mentions Gnulib more prominently.
699 ** New macros to support Objective C.
700 AC_PROG_OBJC, AC_PROG_OBJCPP.
702 * Major changes in Autoconf 2.59b
704 Released 2004-08-20, by Paul Eggert.
707 New macro that computes the default alignment of a type.
709 ** AC_CHECK_TOOL, AC_PATH_TOOL, AC_CHECK_TOOLS
710 When cross-compiling, these macros will give a warning if the tool
711 is not prefixed. In the future, unprefixed cross tools will not
712 be detected; please consult the info documentation for information
713 about the reason of this change.
715 ** AC_CHECK_TARGET_TOOL, AC_PATH_TARGET_TOOL, AC_CHECK_TARGET_TOOLS
716 New macros that detect programs whose name is prefixed with the
717 target type, if the build type and target type are different.
719 ** AC_REQUIRE_AUX_FILE
720 New trace macro that declares expected auxiliary files.
723 New macro that tests for a grep program that accepts as a long a line
726 ** AC_PROG_EGREP, AC_PROG_FGREP
727 These macros now require AC_PROG_GREP, and try EGREP="$GREP -E" and
728 FGREP="$GREP -F" respectively if possible, or else run a path search for
729 a program that accepts as long a line as possible.
732 New macro that tests for a sed program that truncates as few characters
735 * Major changes in Autoconf 2.59
737 Released 2003-11-04, by Akim Demaille
739 ** ac_abs_builddir etc.
740 Absolute file names were actually relative in 2.58.
742 * Major changes in Autoconf 2.58
744 Released 2003-11-04, by Akim Demaille
747 core.* files are no longer removed, as they may be valid user files.
749 ** autoreconf and auxiliary directory
750 Autoreconf creates the auxiliary directory if needed. This is
751 especially useful for initial "bootstrapping" of fresh CVS checkouts.
753 ** AC_CONFIG_MACRO_DIR
754 Use this macro to declare the directory for local M4 macros for aclocal.
757 No longer includes twice the same file in LIBOBJS if invoked
760 ** AC_CONFIG_COMMANDS
761 The directory for its first argument is automatically created. For
764 AC_CONFIG_COMMANDS([src/modules.hh], [...])
766 $top_builddir/src/ is created if needed.
768 ** Autotest and local.at
769 The optional file local.at is always included in Autotest test suites.
772 The warnings are always issued, including with cached runs.
773 This became a significant problem since aclocal and automake can
774 run autoconf behind the scene.
776 ** autoheader warnings
777 The warnings of autoheader can be turned off, using --warning.
778 For instance, -Wno-obsolete disables the complaints about acconfig.h
779 and other deprecated constructs.
782 AC_C_RESTRICT, AC_INCLUDES_DEFAULT, AC_LANG_ASSERT, AC_LANG_WERROR,
785 ** AC_DECL_SYS_SIGLIST
789 Now checks that mktime is the inverse of localtime.
791 ** Improve DJGPP portability
792 The Autoconf tools and configure behave better under DJGPP.
794 ** Present But Cannot Be Compiled
795 New FAQ section dedicated to the mystic
797 configure: WARNING: pi.h: present but cannot be compiled
798 configure: WARNING: pi.h: check for missing prerequisite headers?
799 configure: WARNING: pi.h: proceeding with the preprocessor's result
802 ** Concurrent executions of autom4te
803 autom4te now locks its internal files, which enables concurrent
804 executions of autom4te, likely to happen if automake, autoconf,
805 autoheader etc. are run simultaneously.
808 Use of Libtool 1.5 and higher is encouraged. Compatibility with
809 Libtool pre-1.4 is not checked.
812 Testsuites no longer rerun failed tests in verbose mode; instead,
813 failures are logged while the test is run.
815 In addition, expected failures can be marked as such.
817 * Major changes in Autoconf 2.57
819 Released 2002-12-03 by Paul Eggert.
821 Bug fixes for problems with AIX linker, with freestanding C compilers,
822 with GNU M4 limitations, and with obsolete copies of GNU documents.
824 The Free Documentation License has been upgraded from 1.1 to 1.2.
826 * Major changes in Autoconf 2.56
828 Released 2002-11-15 by Akim Demaille.
830 One packaging problem fixed (config/install-sh was not executable).
832 * Major changes in Autoconf 2.55
834 Released 2002-11-14 by Akim Demaille.
838 Have your configure.ac checked by autoscan ("autoscan").
839 Try the warning options ("autoreconf -fv -Wall").
843 - AC_CHECK_HEADER, AC_CHECK_HEADERS
844 More information on proper use.
846 - Writing Test Programs
848 This sections explains how to write good test sources to use with
849 AC_COMPILE_IFELSE etc. It documents AC_LANG_PROGRAM and so forth.
851 - AC_FOO_IFELSE vs. AC_TRY_FOO
853 Explains why Autoconf moves from AC_TRY_COMPILE etc. to
854 AC_COMPILE_IFELSE and AC_LANG_PROGRAM etc.
858 - Is more robust to different Gettext installations.
860 - Produces messages (when --verbose) to be understood by Emacs'
863 - Supports -W/--warnings.
866 Once the GNU Build System reinstalled, run `./config.status
867 --recheck && ./config.status && make' if possible.
871 - Supports --cache, and --no-cache.
873 - ~/.autom4te.cfg makes it possible to disable the caching mechanism
874 (autom4te.cache). See `Customizing autom4te' in the documentation.
881 Support for the obsoleted options -m, --macrodir, -l, --localdir is
882 dropped in favor of the safer --include/--prepend-include scheme.
887 AC_COMPILER_IFELSE, AC_FUNC_MBRTOWC, AC_HEADER_STDBOOL,
888 AC_LANG_CONFTEST, AC_LANG_SOURCE, AC_LANG_PROGRAM, AC_LANG_CALL,
889 AC_LANG_FUNC_TRY_LINK, AC_MSG_FAILURE, AC_PREPROC_IFELSE.
892 Obsoleted macros are kept for Autoconf backward compatibility, but
893 should be avoided in configure.ac. Running autoupdate is advised.
896 - AC_DEFINE/AC_DEFINE_UNQUOTED
898 We have to stop using the old compatibility scheme --that tried to
899 avoid useless backslashes-- because Libtool 1.4.3 contains a
901 AC_DEFINE([error_t], [int],
902 [Define to a type to use for \`error_t' if it is not
903 otherwise available.])
905 We have to quote the single quotes and backslashes with \. The old
906 compatibility scheme saw that ` was backslashed, and therefore did
907 not quote the single quote... Failure. Hence, Autoconf 2.54 is not
908 compatible with Libtool. Autoconf 2.55 is, but in some cases might
909 produce more \ than wanted.
911 Please, note that in the future the same problem will happen with
912 AC_MSG_*: use `autoreconf -f -Wall'.
916 - Portability of the Autoconf package to Solaris.
918 - Spurious warnings caused by config.status.
919 This bug is benign, but painful: on some systems (typically
920 FreeBSD), warnings such as:
922 config.status: creating Makefile
923 mv: Makefile: set owner/group (was: 1357/0): Operation not permitted
925 could be issued. This is fixed.
928 Simultaneous executions of config.status are possible again.
930 - Precious variables accumulation
932 config.status could stack several copies of the precious variables
936 ** Plans for later versions
940 The compatibility hooks with the old scheme will be completely
941 removed. Please, advice/use `--build', `--host', and `--target'
944 - AC_CHECK_HEADER, AC_CHECK_HEADERS
946 The tests will be stricter, please make sure your invocations are
951 Shell functions will gradually be introduced, probably starting with
952 Autotest. If you know machines which are in use that you suspect
953 *not* to support shell functions, please run the test suite of
954 Autoconf 2.55 on it, and report the results to
955 bug-autoconf@gnu.org.
959 Special characters in AC_MSG_* need not be quoted. Currently,
960 Autoconf has heuristics to decide when a string is escaped, or has
961 to be escaped. This scheme is fragile, and will be removed; the
962 only risk is uglified messages. Please, run `autoreconf -f -Wall'
963 to find occurrences that will be affected.
965 * Major changes in Autoconf 2.54
967 Released 2002-09-13 by Akim Demaille.
971 - autoreconf no longer changes the version of the gettext/po/intl
972 support files. It now adds the files the correspond to the
973 AM_GNU_GETTEXT_VERSION declared in configure.ac.
975 Warning: It now relies on the 'autopoint' program, which is part
976 of GNU gettext 0.11.4 and newer.
978 Please note that you need to have a GNU gettext version that
979 corresponds at least to the AM_GNU_GETTEXT_VERSION declared
980 in configure.ac. You can upgrade to newer GNU gettext versions,
981 though, without needing to change configure.ac.
983 - The -I DIR or --include=DIR option now appends DIR to the include path
984 instead of prepending; this is for consistency with other GNU tools.
985 The new -B DIR or --prepend-include=DIR option has the old behavior.
990 Now handles all the gory details about LIBOBJS and LTLIBOBJS.
991 Please, remove lines such as
993 # This is necessary so that .o files in LIBOBJS are also
994 # built via the ANSI2KNR-filtering rules.
995 LIBOBJS=`echo $LIBOBJS|sed 's/\.o /\$U.o /g;s/\.o$/\$U.o/'`
997 and read the `AC_LIBOBJ vs LIBOBJS' section. Do not define U in
998 your Makefiles either.
1000 - AC_CONFIG_LINKS now makes copies if it can't make links.
1002 - AC_FUNC_FNMATCH now tests only for POSIX compatibility, reverting to
1003 Autoconf 2.13 behavior. The new macro AC_FUNC_FNMATCH_GNU also
1004 tests for GNU extensions to fnmatch, and replaces fnmatch if needed.
1006 - AC_FUNC_SETVBUF_REVERSED no longer fails when cross-compiling.
1008 - AC_PROG_CC_STDC is integrated into AC_PROG_CC.
1010 - AC_PROG_F77 default search no longer includes cf77 and cfg77.
1014 AC_C_BACKSLASH_A, AC_CONFIG_LIBOBJ_DIR, AC_GNU_SOURCE,
1015 AC_PROG_EGREP, AC_PROG_FGREP, AC_REPLACE_FNMATCH,
1016 AC_FUNC_FNMATCH_GNU, AC_FUNC_REALLOC, AC_TYPE_MBSTATE_T.
1018 - AC_FUNC_GETLOADAVG
1019 looks for getloadavg.c in the CONFIG_LIBOBJ_DIR.
1022 Now defines HAVE_MALLOC to 0 if `malloc' does not work, and asks
1023 for an AC_LIBOBJ replacement.
1027 - Spurious complaints from `m4_bmatch' about invalid regular
1028 expressions are suppressed.
1030 - Empty top_builddirs are properly handled.
1032 - AC_CHECK_MEMBER works correctly when the member is an aggregate.
1035 Now colon in the optional path arguments are properly handled.
1037 ** Improved portability
1039 - Both Autoconf the package, and the scripts it produces, should run
1040 more reliably with Zsh. Bear in mind it is the default Bourne shell
1043 - Autoconf and the scripts it produces no longer assume the existence of
1044 the obsolescent commands egrep and fgrep.
1048 - Limitations of Make
1052 The GNATS base moved to
1053 http://bugs.gnu.org/cgi-bin/gnatsweb.pl?database=autoconf
1054 (It is no longer available, though.)
1059 Now contains the list of ouput variables and files (AC_SUBST,
1062 * Major changes in Autoconf 2.53
1064 Released 2002-03-08 by Akim Demaille.
1068 Perl 5.005_03 or later is required: autom4te is written in Perl and is
1069 needed by autoconf. autoheader, autoreconf, ifnames, and autoscan are
1075 Argument requirements, output variables, defined macros.
1076 - M4sugar, M4sh, Autotest
1078 - Double quoting macros
1079 AC_TRY_CPP, AC_TRY_COMPILE, AC_TRY_LINK and AC_TRY_RUN.
1081 The Autoconf manual is now distributed under the terms of the GNU FDL.
1082 - Section `Hosts and Cross-Compilation'
1083 Explains the rationale for the 2.5x changes in the cross-compilation
1084 chain, and in the relationships between build, host, and target
1086 Emphasizes that `cross-compilation' == `--host is given'.
1087 If you are working on compilers etc., be sure to read this section.
1088 - Section `AC_LIBOBJ vs. LIBOBJS'
1089 Explains why assigning LIBOBJS directly is now an error.
1090 Details how to update the code.
1095 Now used instead of hard coded line numbers.
1096 This eases the comparison of `configure's, and diminishes the
1097 pressure over control version archives.
1098 Automatic replacement for shells that don't support this feature.
1099 - New output variables
1100 @builddir@, @top_builddir@, @abs_srcdir@, @abs_top_srcdir@, @abs_builddir@,
1105 Autoconf and Autotest modes are provided.
1110 New, used by the Autoconf suite to cache and speed up most processing.
1112 Supported by autom4te, autoconf and autoheader.
1114 Replaces --autoconf-dir and --localdir in autoconf, autoheader,
1115 autoupdate, and autoreconf.
1117 No longer passes --cygnus, --foreign, --gnits, --gnu, --include-deps:
1118 automake options are to be given via AUTOMAKE_OPTIONS.
1120 Runs gettextize and libtoolize when appropriate.
1122 --m4dir is no longer supported.
1124 Now runs only in the specified directories, defaulting to `.',
1125 but understands AC_CONFIG_SUBDIRS for dependent directories.
1126 Before, it used to run on all the `configure.ac' found in the
1128 Independent packages are properly updated.
1132 - The top level $prefix is propagated to the AC_CONFIG_SUBDIRS configures.
1134 Under the user pressure, $? is finally available. Probably a mistake.
1135 - AC_F77_LIBRARY_LDFLAGS now supports the HP/UX f90 compiler.
1136 - Precious variables accumulation
1137 config.status could stack several copies of the precious variables
1139 - AC_PATH_PROG and family.
1140 Works properly when given a literal path.
1142 Somewhere since 2.13, the result had been reversed.
1146 - AC_C_BIGENDIAN supports the cross-compiling case.
1147 - AC_C_BIGENDIAN accepts ACTION-IF-TRUE, ACTION-IF-FALSE, and
1148 ACTION-IF-UNKNOWN arguments. All are facultative, and the default
1149 for ACTION-IF-TRUE is to define WORDS_BIGENDIAN like AC_C_BIGENDIAN
1151 - AC_C_LONG_DOUBLE now succeeds only if `long double' has more range or
1152 precision than `double'.
1157 It now defines the preprocessor symbols PACKAGE_NAME,
1158 PACKAGE_TARNAME, PACKAGE_VERSION, PACKAGE_STRING, and
1162 Admits a fourth optional parameter: the tar name.
1164 - AC_CONFIG_COMMANDS, HEADERS, FILES, LINKS.
1165 Provide the user with srcdir, ac_srcdir, ac_top_srcdir, ac_builddir,
1166 ac_top_builddir, ac_abs_srcdir, ac_abs_top_srcdir, ac_abs_builddir,
1167 ac_abs_top_builddir.
1169 - AC_CONFIG_COMMANDS, HEADERS, FILES, LINKS and AC_OUTPUT.
1170 Are much less expensive when using long lists of files.
1173 Works with shell variables, and non alphanumeric names.
1177 - AC_FUNC_STRERROR_R now sets STRERROR_R_CHAR_P, not HAVE_WORKING_STRERROR_R,
1178 because POSIX 1003.1-200x draft 7 says strerror_r returns int, not char *.
1180 - AC_FUNC_STRTOD substitutes POW_LIB.
1185 * Major changes in Autoconf 2.52
1187 Released 2001-07-18 by Akim Demaille.
1192 This feature was present in autoconf 2.50 but was not documented.
1193 For example, `@<:@' is translated to `[' just before output. This
1194 is useful when writing strings that contain unbalanced quotes, or
1195 other hard-to-quote constructs.
1196 - m4_pattern_forbid, m4_pattern_allow
1197 - Tips for upgrading from 2.13.
1198 - Using autoscan to maintain a configure.ac.
1201 - Now include stdint.h.
1202 - sys/types.h and sys/stat.h are guarded.
1203 - strings.h is included if available, and not conflicting with string.h.
1206 - The test suite is more robust and presents less false failures.
1207 - Invocation of GNU M4 now robust to POSIXLY_CORRECT.
1208 - configure accepts --prefix='' again.
1209 - AC_CHECK_LIB works properly when its first argument is not a
1211 - HAVE_INTTYPES_H is defined only if not conflicting with sys/types.h.
1212 - build_, host_, and target_alias are AC_SUBST as in 2.13.
1213 - AC_ARG_VAR properly propagates precious variables inherited from the
1214 environment to ./config.status.
1215 - Using --program-suffix/--program-prefix is portable.
1216 - Failures to detect the default compiler's output extension are less
1218 - `config.status foo' works properly when `foo' depends on variables
1219 set in an AC_CONFIG_THING INIT-CMD.
1220 - autoheader is more robust to broken input.
1221 - Fixed Fortran name-mangling and link tests on a number of systems,
1222 e.g. NetBSD; see AC_F77_DUMMY_MAIN, below.
1225 - AC_CHECK_HEADER and AC_CHECK_HEADERS support a fourth argument to
1226 specify pre-includes. In this case, the headers are compiled with
1227 cc, not merely preprocessed by cpp. Therefore it is the _usability_
1228 of a header which is checked for, not just its availability.
1229 - AC_ARG_VAR refuses to run configure when precious variables have
1231 - Versions of compilers are dumped in the logs.
1232 - AC_CHECK_TYPE recognizes use of `foo_t' as a replacement type.
1235 - AC_PATH_XTRA only adds -ldnet to $LIBS if it's needed to link.
1236 - AC_FUNC_WAIT3 and AC_SYS_RESTARTABLE_SYSCALLS are obsoleted.
1237 - AM_FUNC_ERROR_AT_LINE, AM_FUNC_FNMATCH, AM_FUNC_MKTIME,
1238 AM_FUNC_OBSTACK, and AM_FUNC_STRTOD are now activated.
1239 Be sure to read `Upgrading from Version 2.13' to understand why
1240 running `autoupdate' is needed.
1241 - AC_F77_DUMMY_MAIN, AC_F77_MAIN: new macros to detect whether
1242 a main-like routine is required/possible when linking C/C++ with
1243 Fortran. Users of e.g. AC_F77_WRAPPERS should be aware of these.
1244 - AC_FUNC_GETPGRG behaves better when cross-compiling.
1246 * Major changes in Autoconf 2.51
1247 There was no release of Autoconf 2.51 since some packagers had used
1248 this version number without permission to ship intermediary versions
1249 of 2.50. The version was skipped to avoid confusion.
1251 * Major changes in Autoconf 2.50
1253 Released 2001-05-21 by Akim Demaille.
1255 ** Lots of bug fixes
1256 There have been far too many to enumerate them here. Check out
1257 ChangeLog if you really want to know more.
1259 ** Improved documentation
1260 In particular, portability issues are better covered.
1263 All the standard GNU Makefile targets are supported. The layout has
1264 changed: m4/ holds the M4 extensions Autoconf needs for its
1265 configuration, doc/ contains the documentation, and tests/ contains
1268 ** Man pages are provided
1269 For autoconf, autoreconf, autoupdate, autoheader, autoscan, ifnames,
1270 config.guess, config.sub.
1274 Provides a safe and powerful means to trace the macro uses. This
1275 provide the parsing layer for tools which need to `study'
1279 Specify what category of warnings should be enabled.
1281 - When recursing into subdirectories, try for configure.gnu before
1282 configure to adapt for packages not using autoconf on case-insensitive
1286 More errors are now caught (circular AC_REQUIRE dependencies,
1287 AC_DEFINE in the action part of an AC_CACHE_CHECK, too many pops
1288 etc.). In addition, their location and call stack are given.
1291 autoupdate is much more powerful, and is able to provide the glue code
1292 which might be needed to move from an old macro to its newer
1295 You are strongly encouraged to use it to modernize both your
1296 `configure.in' and your .m4 extension files.
1299 The internal machinery of autoheader has completely changed. As a
1300 result, using `acconfig.h' should be considered to be obsoleted, and
1301 you are encouraged to get rid of it using the AH macros.
1306 ** Fortran 77 compilers
1307 Globally, the support for Fortran 77 is considerably improved.
1309 Support for automatically determining a Fortran 77 compiler's
1310 name-mangling scheme. New CPP macros F77_FUNC and F77_FUNC_ are
1311 provided to wrap C/C++ identifiers, thus making it easier and more
1312 transparent for C/C++ to call Fortran 77 routines, and Fortran 77 to
1313 call C/C++ routines. See the Texinfo documentation for details.
1316 The test suite no longer uses DejaGNU. It should be easy to submit
1317 test cases in this new framework.
1320 - --help, --help=long, -hl
1321 no longer dumps useless items.
1323 lists only specific options.
1324 - --help=recursive, -hr
1325 displays the help of all the embedded packages.
1326 - Remembers environment variables when reconfiguring.
1327 The previous scheme to set envvar before running configure was
1329 what prevented configure from remembering the environment in which
1330 it was run, therefore --recheck was run in an inconsistent
1331 environment. Now, one should run
1333 and then --recheck will work properly. Variables declared with
1334 AC_ARG_VAR are also preserved.
1336 $build defaults to `config.guess`, $host to $build, and then $target
1338 Cross-compilation is a global status of the package, it no longer
1339 depends upon the current language.
1340 Cross compilation is enabled iff the user specified `--host'.
1341 `configure' now fails if it can't run the executables it compiles,
1342 unless cross-compilation is enabled.
1344 The cache file is disabled by default. The new options
1345 `--config-cache', `-C' set the cache to `config.cache'.
1349 Much faster on most architectures.
1350 - concurrent executions
1351 It is safe to use `make -j' with config.status.
1352 - human interface improved
1353 It is possible to invoke
1354 ./config.status foobar
1355 instead of the former form (still valid)
1356 CONFIG_COMMANDS= CONFIG_HEADERS= CONFIG_LINKS= \
1357 CONFIG_FILES=foobar:foo.in:bar.in \
1359 The same holds for configuration headers and links.
1360 You can instantiate unknown files and headers:
1361 ./config.status --header foo.h:foo.h.in --file bar:baz
1362 - has a useful --help
1363 - accepts special file name "-" for stdin/stdout
1368 Specify additional copyright information.
1371 Now expects the identity of the package as argument.
1375 Most macros, if not all, now strictly follow the `one quotation
1376 level' rule. This results in a more predictable expansion.
1379 A sly bug in the AC_REQUIRE machinery, which could produce incorrect
1380 configure scripts, was fixed by Axel Thimm.
1384 Document and ask for the registration of an envvar.
1387 Specifies the file which `configure' should look for when trying to
1388 find the source tree (used to be handled by AC_INIT).
1390 - AC_CONFIG_COMMANDS
1391 To add new actions to config.status. Should be used instead of
1395 Replaces AC_LINK_FILES.
1397 - AC_CONFIG_HEADERS, AC_CONFIG_COMMANDS, AC_CONFIG_SUBDIRS,
1398 AC_CONFIG_LINKS, and AC_CONFIG_FILES
1399 They now obey sh: you should no longer use shell variables as
1400 argument. Instead of
1402 test "$package_foo_enabled" = yes && $my_subdirs="$my_subdirs foo"
1403 AC_CONFIG_SUBDIRS($my_subdirs)
1407 if test "$package_foo_enabled" = yes; then
1408 AC_CONFIG_SUBDIRS(foo)
1412 To format an Autoconf macro's help string so that it looks pretty
1413 when the user executes `configure --help'.
1416 ** Generic Test Macros
1418 The interface of the AC_CHECK families of macros (decl, header,
1419 type, member, func) is now uniform. They support the same set of
1422 - AC_CHECK_DECL, AC_CHECK_DECLS
1423 To check whether a symbol is declared.
1425 - AC_CHECK_SIZEOF, AC_C_CHAR_UNSIGNED.
1426 No longer need a cross-compilation default.
1429 The test it performs is much more robust than previously, and makes
1430 it possible to test builtin types in addition to typedefs.
1431 It is now schizophrenic:
1432 - AC_CHECK_TYPE(TYPE, REPLACEMENT)
1433 remains for backward compatibility, but its use is discouraged.
1434 - AC_CHECK_TYPE(TYPE, IF-FOUND, IF-NOT-FOUND, INCLUDES)
1435 behaves exactly like the other AC_CHECK macros.
1438 Checks whether given types are supported by the system.
1440 - AC_CHECK_MEMBER, AC_CHECK_MEMBERS
1441 Check for given members in aggregates (e.g., pw_gecos in struct
1445 Checks if the compiler supports ISO C, included when needs special
1449 Checking whether the preprocessor indicates missing includes by the
1450 error code. stderr is checked by AC_TRY_CPP only as a fallback.
1453 Takes a language as argument and replaces AC_LANG_C,
1454 AC_LANG_CPLUSPLUS and AC_LANG_FORTRAN77.
1456 - AC_LANG_PUSH, AC_LANG_POP
1457 Are preferred to AC_LANG_SAVE, AC_LANG_RESTORE.
1460 - AC_FUNC_CHOWN, AC_FUNC_MALLOC, AC_FUNC_STRERROR_R,
1461 AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK, AC_FUNC_STAT, AC_FUNC_LSTAT,
1462 AC_FUNC_ERROR_AT_LINE, AC_FUNC_OBSTACK, AC_FUNC_STRTOD, AC_FUNC_FSEEKO.
1466 Sets GETGROUPS_LIBS.
1468 - AC_FUNC_GETLOADAVG
1469 Defines `HAVE_STRUCT_NLIST_N_UN_N_NAME' instead of `NLIST_NAME_UNION'.
1472 Now integrates `AC_DECL_YYTEXT' which is obsoleted.
1475 Arrange for large-file support.
1477 - AC_EXEEXT, AC_OBJEXT
1478 You are no longer expected to use them: their computation is
1479 performed by default.
1481 ** C++ compatibility
1482 Every macro has been revisited in order to support at best CC=c++.
1484 Major changes in Autoconf 2.14:
1485 There was no release of GNU Autoconf 2.14.
1487 Major changes in Autoconf 2.13:
1489 Released 1999-05-01 by Ben Elliston.
1491 * Support for building on Win32 systems where the only available C or
1492 C++ compiler is the Microsoft Visual C++ command line compiler
1493 (`cl'). Additional support for building on Win32 systems which are
1494 using the Cygwin or Mingw32 environments.
1495 * Support for alternative object file and executable file extensions.
1496 On Win32, for example, these are .obj and .exe. These are discovered
1497 using AC_OBJEXT and AC_EXEEXT, which substitute @OBJEXT@ and
1498 @EXEEXT@ in the output, respectively.
1499 * New macros: AC_CACHE_LOAD, AC_CACHE_SAVE, AC_FUNC_SELECT_ARGTYPES,
1500 AC_VALIDATE_CACHED_SYSTEM_TUPLE, AC_SEARCH_LIBS, AC_TRY_LINK_FUNC,
1501 AC_C_STRINGIZE, AC_CHECK_FILE(S), AC_PROG_F77 (and friends).
1502 * AC_DEFINE now has an optional third argument for a description to be
1503 placed in the config header input file (e.g. config.h.in).
1504 * The C++ code fragment compiled for the C++ compiler test had to be
1505 improved to include an explicit return type for main(). This was
1506 causing failures on systems using recent versions of the EGCS C++
1508 * Fixed an important bug in AC_CHECK_TYPE that would cause a configure
1509 script to report that `sometype_t' was present when only `type_t'
1511 * Merge of the FSF version of config.guess and config.sub to modernize
1512 these scripts. Add support for a few new hosts in config.guess.
1513 Incorporate latest versions of install-sh, mkinstalldirs and
1514 texinfo.tex from the FSF.
1515 * autoreconf is capable of running automake if necessary (and
1517 * Support for Fortran 77. See the Texinfo documentation for details.
1518 * Bug fixes and workarounds for quirky bugs in vendor utilities.
1520 Major changes in Autoconf 2.12:
1522 Released 1996-11-26 by David J. MacKenzie
1524 * AC_OUTPUT and AC_CONFIG_HEADER can create output files by
1525 concatenating multiple input files separated by colons, like so:
1526 AC_CONFIG_HEADER(config.h:conf.pre:config.h.in:conf.post)
1527 AC_OUTPUT(Makefile:Makefile.in:Makefile.rules)
1528 The arguments may be shell variables, to compute the lists on the fly.
1529 * AC_LINK_FILES and AC_CONFIG_SUBDIRS may be called multiple times.
1530 * New macro AC_OUTPUT_COMMANDS adds more commands to run in config.status.
1533 Major changes in Autoconf 2.11:
1535 Released November 18th, 1996, by David J. MacKenzie
1537 * AC_PROG_CC and AC_PROG_CXX check whether the compiler works.
1538 They also default CFLAGS/CXXFLAGS to "-g -O2" for gcc, instead of "-g -O".
1539 * AC_REPLACE_FUNCS defines HAVE_foo if the system has the function `foo'.
1540 * AC_CONFIG_HEADER expands shell variables in its argument.
1541 * New macros: AC_FUNC_FNMATCH, AC_FUNC_SETPGRP.
1542 * The "checking..." messages and the source code for test programs that
1543 fail are saved in config.log.
1544 * Another workaround has been added for seds with small command length limits.
1545 * config.sub and config.guess recognize more system types.
1548 Major changes in Autoconf 2.10:
1550 Released May 7th, 1996, by Roland McGrath
1553 * The cache variable names used by `AC_CHECK_LIB(LIB, FUNC, ...)' has
1554 changed: now $ac_cv_lib_LIB_FUNC, previously $ac_cv_lib_LIB.
1556 Major changes in Autoconf 2.9:
1558 Released March 16th, 1996, by Roland McGrath
1562 Major changes in Autoconf 2.8:
1564 Released March 8th, 1996, by Roland McGrath
1568 Major changes in Autoconf 2.7:
1570 Released November 22nd, 1995, by David J. MacKenzie
1574 Major changes in Autoconf 2.6:
1576 Released November 20th, 1995, by David J. MacKenzie
1580 Major changes in Autoconf 2.5:
1582 Released November 17th, 1995, by Roland McGrath
1584 * New configure options --bindir, --libdir, --datadir, etc., with
1585 corresponding output variables.
1586 * New macro: AC_CACHE_CHECK, to make using the cache easier.
1587 * config.log contains the command being run as well as any output from it.
1588 * AC_CHECK_LIB can check for libraries with "." or "/" or "+" in their name.
1589 * AC_PROG_INSTALL doesn't cache a name for install-sh, for sharing caches.
1590 * AC_CHECK_PROG, AC_PATH_PROG, AC_CHECK_PROGS, AC_PATH_PROGS, and
1591 AC_CHECK_TOOL can search a path other than $PATH.
1592 * AC_CHECK_SIZEOF takes an optional size to use when cross-compiling.
1594 Major changes in Autoconf 2.4:
1596 Released June 14th, 1995, by David J. MacKenzie
1598 * Fix a few bugs found by Emacs testers.
1600 Major changes in Autoconf 2.3:
1602 Released March 27th, 1995, by David J. MacKenzie
1604 * Fix the cleanup trap in several ways.
1605 * Handle C compilers that are picky about option placement.
1606 * ifnames gets the version number from the right directory.
1608 Major changes in Autoconf 2.2:
1610 Released March 8th, 1995, by David J. MacKenzie
1612 * The ifnames utility is much faster but requires a "new awk" interpreter.
1613 * AC_CHECK_LIB and AC_HAVE_LIBRARY check and add the new
1614 library before existing libs, not after, in case it uses them.
1615 * New macros: AC_FUNC_GETPGRP, AC_CHECK_TOOL.
1616 * Lots of bug fixes.
1617 * Many additions to the TODO file :-)
1619 Major changes in Autoconf 2.1:
1621 Released November 4th, 1994, by David J. MacKenzie
1624 * More explanations in the manual.
1625 * Fix a spurious failure in the testsuite.
1626 * Clarify some warning messages.
1627 * autoreconf by default only rebuilds configure and config.h.in files
1628 that are older than any of their particular input files; there is a
1629 --force option to use after installing a new version of Autoconf.
1631 Thanks to everybody who's submitted changes and additions to Autoconf!
1632 I've incorporated many of them, and am still considering others for
1633 future releases -- but I didn't want to postpone this release indefinitely.
1635 Caution: don't indiscriminately rebuild configure scripts with
1636 Autoconf version 2. Some configure.in files need minor adjustments to
1637 work with it; the documentation has a chapter on upgrading. A few
1638 configure.in files, including those for GNU Emacs and the GNU C
1639 Library, need major changes because they relied on undocumented
1640 internals of version 1. Future releases of those packages will have
1641 updated configure.in files.
1643 It's best to use GNU M4 1.3 (or later) with Autoconf version 2.
1644 Autoconf now makes heavy use of M4 diversions, which were implemented
1645 inefficiently in GNU M4 releases before 1.3.
1647 Major changes in Autoconf 2.0:
1649 Released October 26th, 1994, by David J. MacKenzie
1651 ** New copyright terms:
1652 * There are no restrictions on distribution or use of configure scripts.
1655 * Autoconf manual is reorganized to make information easier to find
1656 and has several new indexes.
1657 * INSTALL is reorganized and clearer and is now made from Texinfo source.
1660 * autoscan to generate a preliminary configure.in for a package by
1661 scanning its source code for commonly used nonportable functions,
1662 programs, and header files.
1663 * ifnames to list the symbols used in #if and #ifdef directives in a
1665 * autoupdate to update a configure.in to use the version 2 macro names.
1666 * autoreconf to recursively remake configure and configuration header
1667 files in a source tree.
1669 ** Changed utilities:
1670 * autoheader can take pieces of acconfig.h to replace config.h.{top,bot}.
1671 * autoconf and autoheader can look for package-local definition files
1672 in an alternate directory.
1675 * AC_CACHE_VAL to share results of tests between configure runs.
1676 * AC_DEFUN to define macros, automatically AC_PROVIDE them, and ensure
1677 that macros invoked with AC_REQUIRE don't interrupt other macros.
1678 * AC_CONFIG_AUX_DIR, AC_CANONICAL_SYSTEM, AC_CANONICAL_HOST, AC_LINK_FILES to
1679 support deciding unguessable features based on the host and target types.
1680 * AC_CONFIG_SUBDIRS to recursively configure a source tree.
1681 * AC_ARG_PROGRAM to use the options --program-prefix,
1682 --program-suffix, and --program-transform-name to change the names
1683 of programs being installed.
1684 * AC_PREFIX_DEFAULT to change the default installation prefix.
1685 * AC_TRY_COMPILE to compile a test program without linking it.
1686 * AC_CHECK_TYPE to check whether sys/types.h or stdlib.h defines a given type.
1687 * AC_CHECK_LIB to check for a particular function and library.
1688 * AC_MSG_CHECKING and AC_MSG_RESULT to print test results, on a single line,
1689 whether or not the test succeeds. They obsolete AC_CHECKING and AC_VERBOSE.
1690 * AC_SUBST_FILE to insert one file into another.
1691 * AC_FUNC_MEMCMP to check whether memcmp is 8-bit clean.
1692 * AC_FUNC_STRFTIME to find strftime even if it's in -lintl.
1693 * AC_FUNC_GETMNTENT to find getmntent even if it's in -lsun or -lseq.
1694 * AC_HEADER_SYS_WAIT to check whether sys/wait.h is POSIX.1 compatible.
1697 * Many macros renamed systematically, but old names are accepted for
1698 backward compatibility.
1699 * AC_OUTPUT adds the "automatically generated" comment to
1700 non-Makefiles where it finds @configure_input@ in an input file, to
1701 support files with various comment syntaxes.
1702 * AC_OUTPUT does not replace "prefix" and "exec_prefix" in generated
1703 files when they are not enclosed in @ signs.
1704 * AC_OUTPUT allows the optional environment variable CONFIG_STATUS to
1705 override the file name "config.status".
1706 * AC_OUTPUT takes an optional argument for passing variables from
1707 configure to config.status.
1708 * AC_OUTPUT and AC_CONFIG_HEADER allow you to override the input-file names.
1709 * AC_OUTPUT automatically substitutes the values of CFLAGS, CXXFLAGS,
1710 CPPFLAGS, and LDFLAGS from the environment.
1711 * AC_PROG_CC and AC_PROG_CXX now set CFLAGS and CXXFLAGS, respectively.
1712 * AC_PROG_INSTALL looks for install-sh or install.sh in the directory
1713 specified by AC_CONFIG_AUXDIR, or srcdir or srcdir/.. or
1714 srcdir/../.. by default.
1715 * AC_DEFINE, AC_DEFINE_UNQUOTED, and AC_SUBST are more robust and smaller.
1716 * AC_DEFINE no longer prints anything, because of the new result reporting
1717 mechanism (AC_MSG_CHECKING and AC_MSG_RESULT).
1718 * AC_VERBOSE pays attention to --quiet/--silent, not --verbose.
1719 * AC_ARG_ENABLE and AC_ARG_WITH support whitespace in the arguments to
1720 --enable- and --with- options.
1721 * AC_CHECK_FUNCS and AC_CHECK_HEADERS take optional shell commands to
1722 execute on success or failure.
1723 * Checking for C functions in C++ works.
1726 * AC_REMOTE_TAPE and AC_RSH removed; too specific to tar and cpio, and
1727 better maintained with them.
1728 * AC_ARG_ARRAY removed because no one was likely using it.
1729 * AC_HAVE_POUNDBANG replaced with AC_SYS_INTERPRETER, which doesn't
1730 take arguments, for consistency with all of the other specific checks.
1733 * Comes with config.sub and config.guess, and uses them optionally.
1734 * Uses config.cache to cache test results. An alternate cache file
1735 can be selected with the --cache-file=FILE option.
1736 * Uses optional shell scripts $prefix/share/config.site and
1737 $prefix/etc/config.site to perform site or system specific initializations.
1738 * configure saves compiler output to ./config.log for debugging.
1739 * New files autoconf.m4 and autoheader.m4 load the other Autoconf macros.
1740 * acsite.m4 is the new name for the system-wide aclocal.m4.
1741 * Has a DejaGnu test suite.
1743 Major changes in Autoconf 1.11:
1745 * AC_PROG_INSTALL calls install.sh with the -c option.
1746 * AC_SET_MAKE cleans up after itself.
1747 * AC_OUTPUT sets prefix and exec_prefix if they weren't set already.
1748 * AC_OUTPUT prevents shells from looking in PATH for config.status.
1750 Plus a few other bug fixes.
1752 Major changes in Autoconf 1.10:
1754 * autoheader uses config.h.bot if present, analogous to config.h.top.
1755 * AC_PROG_INSTALL looks for install.sh in srcdir or srcdir/.. and
1757 * AC_PROG_CXX looks for cxx as a C++ compiler.
1759 Plus several bugs fixed.
1761 Major changes in Autoconf 1.9:
1763 * AC_YYTEXT_POINTER replaces AC_DECLARE_YYTEXT.
1764 * AC_SIZEOF_TYPE generates the cpp symbol name automatically,
1765 and autoheader generates entries for those names automatically.
1766 * AC_FIND_X gets the result from xmkmf correctly.
1767 * AC_FIND_X assumes no X if --without-x was given.
1768 * AC_FIND_XTRA adds libraries to the variable X_EXTRA_LIBS.
1769 * AC_PROG_INSTALL finds OSF/1 installbsd.
1771 Major changes in Autoconf 1.8:
1774 * New macros AC_LANG_C, AC_LANG_CPLUSPLUS, AC_LANG_SAVE, AC_LANG_RESTORE,
1775 AC_PROG_CXX, AC_PROG_CXXCPP, AC_REQUIRE_CPP
1776 for checking both C++ and C features in one configure script.
1777 * New macros AC_CHECKING, AC_VERBOSE, AC_WARN, AC_ERROR for printing messages.
1778 * New macros AC_FIND_XTRA, AC_MMAP, AC_SIZEOF_TYPE, AC_PREREQ,
1779 AC_SET_MAKE, AC_ENABLE.
1782 * AC_FIND_X looks for X in more places.
1783 * AC_PROG_INSTALL defaults to install.sh instead of cp, if it's in srcdir.
1784 install.sh is distributed with Autoconf.
1785 * AC_DECLARE_YYTEXT has been removed because it can't work, pending
1786 a rewrite of quoting in AC_DEFINE.
1787 * AC_OUTPUT adds its comments in C format when substituting in C files.
1788 * AC_COMPILE_CHECK protects its ECHO-TEXT argument with double quotes.
1790 ** New or changed command line options:
1791 * configure accepts --enable-FEATURE[=ARG] and --disable-FEATURE options.
1792 * configure accepts --without-PACKAGE, which sets withval=no.
1793 * configure accepts --x-includes=DIR and --x-libraries=DIR.
1794 * Giving --with-PACKAGE no argument sets withval=yes instead of withval=1.
1795 * configure accepts --help, --version, --silent/--quiet, --no-create options.
1796 * configure accepts and ignores most other Cygnus configure options, and
1797 warns about unknown options.
1798 * config.status accepts --help, --version options.
1800 ** File names and other changes:
1801 * Relative srcdir values are not made absolute.
1802 * The values of @prefix@ and @exec_prefix@ and @top_srcdir@ get substituted.
1803 * Autoconf library files are installed in ${datadir}/autoconf, not ${datadir}.
1804 * autoheader optionally copies config.h.top to the beginning of config.h.in.
1805 * The example Makefile dependencies for configure et al. work better.
1806 * Namespace cleanup: all shell variables used internally by Autoconf
1807 have names beginning with `ac_'.
1809 More big improvements are in process for future releases, but have not
1810 yet been (variously) finished, integrated, tested, or documented enough
1813 Major changes in Autoconf 1.7:
1815 * New macro AC_OBSOLETE.
1816 * Bugs in Makefile.in fixed.
1817 * AC_LONG_FILE_NAMES improved.
1819 Major changes in Autoconf 1.6:
1821 * New macro AC_LONG_64_BITS.
1822 * Multiple .h files can be created.
1823 * AC_FIND_X looks for X files directly if it doesn't find xmkmf.
1824 * AC_ALLOCA defines C_ALLOCA if using alloca.c.
1825 * --with-NAME can take a value, e.g., --with-targets=sun4,hp300bsd.
1826 * Unused --no-create option to configure removed.
1827 * autoheader doesn't change the timestamp of its output file if
1828 the file didn't change.
1829 * All macros that look for libraries now use AC_HAVE_LIBRARY.
1830 * config.status checks three optional environment variables to
1831 modify its behavior.
1832 * The usual bug fixes.
1834 Major changes in Autoconf 1.5:
1836 * New macros AC_FIND_X, AC_OFF_T, AC_STAT_MACROS_BROKEN, AC_REVISION.
1837 * autoconf and autoheader scripts have GNU standards conforming
1838 --version and --help options (they print their message and exit).
1841 Major changes in Autoconf 1.4:
1843 * New macros AC_HAVE_POUNDBANG, AC_TIME_WITH_SYS_TIME, AC_LONG_DOUBLE,
1844 AC_GETGROUPS_T, AC_DEFINE_UNQUOTED.
1845 * autoconf and autoheader use the M4 environment variable to determine the
1846 name of the M4 program to use.
1847 * The --macrodir option to autoconf and autoheader specifies the directory
1848 in which acspecific.m4, acgeneral.m4, etc. reside if not the default.
1849 * autoconf and autoheader can take `-' as their file names, which means to
1850 read stdin as input.
1851 * Resulting configure scripts can take a --verbose option which causes them
1852 to print the results of their tests.
1853 * AC_DEFINE quotes its second argument in such a way that spaces, magic
1854 shell characters, etc. will be preserved during various stages of
1855 expansion done by the shell. If you don't want this, use
1856 AC_DEFINE_UNQUOTED instead.
1857 * Much textual processing done with external calls to tr and sed have been
1858 internalized with builtin M4 `patsubst' and `translit' calls.
1859 * AC_OUTPUT doesn't hardwire the file names it outputs. Instead, you can
1860 set the shell variables `gen_files' and `gen_config' to the list of
1861 file names to output.
1862 * AC_DECLARE_YYTEXT does an AC_SUBST of `LEX_OUTPUT_ROOT', which may be
1863 "lex.yy" or "lexyy", depending on the system.
1864 * AC_PROGRAMS_CHECK takes an optional third arg. If given, it is used as
1866 * If AC_ALLOCA chooses alloca.c, it also defines STACK_DIRECTION.
1867 * AC_CONST works much more reliably on more systems.
1870 Major changes in Autoconf 1.3:
1872 configure no longer requires awk for packages that use a config.h.
1873 Support handling --with-PACKAGE options.
1874 New `autoheader' script to create `config.h.in' from `configure.in'.
1875 Ignore troublesome -lucb and -lPW when searching for alloca.
1876 Rename --exec_prefix to --exec-prefix for GNU standards conformance.
1877 Improve detection of STDC library.
1878 Add AC_HAVE_LIBRARY to check for non-default libraries.
1879 Function checking should work with future GNU libc releases.
1881 Major changes in Autoconf 1.2:
1883 The --srcdir option is now usually unnecessary.
1884 Add a file containing sample comments describing CPP macros.
1885 A comment in config.status tells which host it was configured on.
1886 Substituted variable values can now contain commas.
1887 Fix bugs in various feature checks.
1889 Major changes in Autoconf 1.1:
1891 Added AC_STRCOLL macro.
1892 Made AC_GETLOADAVG check for more things.
1893 AC_OUTPUT argument is now optional.
1898 Copyright (C) 1993, 1994, 1995, 1996, 1998, 1999, 2000, 2001, 2002,
1899 2003, 2004, 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc.
1901 Copying and distribution of this file, with or without modification,
1902 are permitted in any medium without royalty provided the copyright
1903 notice and this notice are preserved. This file is offered as-is,
1904 without warranty of any kind.