1 GNU Autoconf NEWS - User visible changes.
3 * Major changes in Autoconf 2.65a (????-??-??) [experimental]
6 ** AC_FUNC_MMAP works in C++ mode again. Regression introduced in 2.65.
8 ** Use of m4_divert without a named diversion now issues a syntax warning,
9 since it is seldom right to change diversions behind autoconf's back.
11 ** The macros AC_TYPE_INT8_T, AC_TYPE_INT16_T, AC_TYPE_INT32_T, and
12 AC_TYPE_INT64_T work again. Regression introduced in 2.65.
14 ** AC_PROG_INSTALL correctly uses `shtool' again. Regression introduced
17 ** Autoconf should work on EBCDIC hosts.
19 * Major changes in Autoconf 2.65 (2009-11-21) [stable]
20 Released by Eric Blake, based on git versions 2.64.*.
22 ** Autoconf is now licensed under the General Public License version 3
23 or later (GPLv3+). As with earlier versions, the license includes
24 an exception clause so that you may release a configure script
25 generated by autoconf under the license of your own program.
27 ** New macros to support Objective C++.
28 AC_PROG_OBJCXX AC_PROG_OBJCXXCPP
30 ** The following undocumented autoconf macros, removed in Autoconf 2.64,
34 These macros are present only for backwards compatibility purposes.
36 ** The macro AC_LANG_COMPILER no longer fails on embedded systems that
37 lack fopen in the C library, such as AVR or RTEMS (regression
40 ** The AC_FC_FREEFORM macro no longer suffers from a whitespace bug that
41 made it fail with some Fortran compilers (regression introduced in
44 ** The AC_TYPE_UINT64_T and AC_TYPE_INT64_T macros have been fixed to no
45 longer mistakenly select a 32-bit type on some compilers (bug present
46 since macros were introduced in 2.59c).
48 ** The AC_FUNC_MMAP macro has been fixed to be portable to systems like
49 Cygwin (bug present since macro was introduced in 2.0).
51 ** The following documented autotest macros are new:
54 ** The following m4sugar macros now quote their expansion:
57 ** The following m4sugar macros are new:
60 ** The m4sugar macro m4_text_wrap now copes with embedded quoting without
61 requiring quadrigraphs. For uses like AC_ARG_VAR([a], [[b c]]),
62 this gives the intuitive behavior of "[b c]" in the output (2.63
63 gave the output of "[b], [c]", and 2.64 encountered a failure).
65 ** The `$tmp' temporary directory used in config.status is documented for
68 ** config.status now provides a --config option to produce the configuration.
70 ** Many cache variables used by Autoconf's macros are now documented.
72 ** Configure scripts work better on DJGPP by avoiding a bug present in
73 the DJGPP port of bash 2.04 in handling 'return' in a shell
74 function (regression introduced in 2.64).
76 * Major changes in Autoconf 2.64 (2009-07-26) [stable]
77 Released by Eric Blake, based on git versions 2.63b.*.
79 ** Autoconf now requires GNU M4 1.4.6 or later. Earlier versions of M4
80 have a bug in regular expression handling that interferes with some
81 of the speedups provided since Autoconf 2.63. GNU M4 1.4.13 or
84 ** AS_IF and AS_CASE have been taught to avoid syntax errors even when
85 given arguments that expand to just whitespace.
87 ** The following documented autoconf macros are new:
88 AC_ERLANG_SUBST_ERTS_VER
90 ** The autoheader tool now understands m4 macro arguments passed to
91 AC_DEFINE and AC_DEFINE_UNQUOTED.
93 ** Ensure AT_CHECK can support commands that include a # given with
94 proper m4 quoting. For shell comments, this is a new feature; for
95 non-shell comments, this fixes a regression introduced in 2.63b.
96 Additionally, AT_CHECK correctly supplies shell escapes for
97 metacharacters occurring in m4 macro expansions within the expected
98 stdout and stderr parameters.
100 ** The macro AT_CHECK now understands the concept of hard failure. If
101 a test exits with an unexpected status 99, cleanup actions for the
102 test are inhibited and the test is treated as a failure regardless
103 of AT_XFAIL_IF. It also understands the new directives
104 ignore-nolog, stdout-nolog, and stderr-nolog.
106 ** The following documented autotest macros are new:
107 AT_CHECK_UNQUOTED AT_FAIL_IF AT_SKIP_IF
109 ** The following documented m4sugar macros are new:
110 m4_argn m4_copy_force m4_default_nblank m4_default_nblank_quoted
111 m4_ifblank m4_ifnblank m4_rename_force
113 ** The autoconf testsuite now exercises all Erlang macros.
115 * Major changes in Autoconf 2.63b (2009-03-31) [beta]
116 Released by Eric Blake, based on git versions 2.63.*.
118 ** The manual is now shipped under the terms of the GNU FDL 1.3.
120 ** AC_REQUIRE now detects the case of an outer macro which first expands
121 then later indirectly requires the same inner macro. Previously,
122 this case led to silent out-of-order expansion (bug present since
123 2.50); it now issues a syntax warning, and duplicates the expansion
124 of the inner macro to guarantee dependencies have been met. See
125 the manual for advice on how to refactor macros in order to avoid
126 the bug in earlier autoconf versions and avoid increased script
127 size in the current version.
129 ** AC_DEFUN_ONCE has improved semantics. Previously, a macro declared
130 with AC_DEFUN_ONCE warned on a second invocation; and out-of-order
131 expansion was still possible. Now, dependencies are guaranteed,
132 and subsequent invocations are a silent no-op. This makes
133 AC_DEFUN_ONCE an ideal macro for silencing AC_REQUIRE warnings.
135 ** The following macros are now defined with AC_DEFUN_ONCE. This means
136 a subtle change in semantics; previously, an AC_DEFUN macro could
137 expand one of these macros multiple times or surround the macro
138 inside shell conditional text to bypass the effects of these
139 macros, but now the macro will expand exactly once, and prior to
140 the start of any enclosing AC_DEFUN macro:
141 AC_CANONICAL_BUILD AC_CANONICAL_HOST AC_CANONICAL_TARGET
142 AC_HEADER_ASSERT AC_PROG_INSTALL AC_PROG_MKDIR_P
143 AC_USE_SYSTEM_EXTENSIONS
145 ** AC_LANG_ERLANG works once again (regression introduced in 2.61a).
147 ** AC_HEADER_ASSERT is fixed so that './configure --enable-assert' no
148 longer mistakenly disables assertions.
150 ** AC_INIT now takes an optional fifth parameter that can be used to
151 set AC_PACKAGE_URL, a URL for the package's home page; the URL is
152 used in `configure --help' and is also available via AC_DEFINE.
154 ** Autotest testsuites accept an option --jobs[=N] for parallel testing.
155 This feature is still in testing, and may not work on every
156 platform, help in improving it would be appreciated.
158 ** Autotest testsuites do not attempt to write startup error messages
159 to the log file before that is opened (regression introduced in 2.63).
161 ** Configure scripts now use shell functions. This feature leads to
162 smaller configure files and faster execution.
164 ** Present But Cannot Be Compiled: Autoconf will now proceed with
165 the compiler's result if a header is present but cannot be compiled.
166 The warning is still printed, and you should really fix it by
167 providing a fourth parameter to AC_CHECK_HEADER/AC_CHECK_HEADERS.
169 ** Autoreconf added aclocal to the set of programs affected by the
170 `autoreconf -I dir' option.
172 ** The following documented m4sugar macros are new:
173 m4_chomp m4_chomp_all m4_cleardivert m4_curry m4_default_quoted
174 m4_esyscmd_s m4_map_args m4_map_args_pair m4_map_args_sep
175 m4_map_args_w m4_set_map m4_set_map_sep m4_stack_foreach
176 m4_stack_foreach_lifo m4_stack_foreach_sep
177 m4_stack_foreach_sep_lifo
179 ** The following m4sugar macros are documented now, but in some cases
180 with slightly different semantics than what the previous
181 undocumented version had:
182 m4_copy m4_dumpdefs m4_rename m4_version_prereq
184 ** The m4sugar macro m4_expand has been taught to handle unterminated
185 comments and shell case statements. As a result, it is used
186 internally in more places, such as AC_DEFINE and AT_CHECK. Most
187 uses of AC_DEFINE and AT_CHECK should not behave any differently;
188 however, it may be necessary to add double-quoting around
189 unbalanced `(' where single-quoting used to be sufficient.
191 ** The following documented m4sh macros are new:
192 AS_INIT_GENERATED AS_LINENO_PREPARE AS_ME_PREPARE AS_SET_STATUS
193 AS_VAR_APPEND AS_VAR_ARITH AS_VAR_COPY
195 ** The following m4sh macros are documented now, but in some cases
196 with slightly different semantics than what the previous
197 undocumented version had:
198 AS_ECHO AS_ECHO_N AS_ESCAPE AS_EXIT AS_LITERAL_IF AS_UNSET
199 AS_VAR_IF AS_VAR_POPDEF AS_VAR_PUSHDEF AS_VAR_SET AS_VAR_SET_IF
200 AS_VAR_TEST_SET AS_VERSION_COMPARE
202 ** The m4sh macros AS_IF and AS_CASE can now be used in shell lists.
203 The responsibility for supplying a trailing newline now belongs to
204 the call site, but since most users did not add dnl, this generally
205 results in fewer empty lines in configure.
208 * Major changes in Autoconf 2.63 (2008-09-09) [stable]
209 Released by Eric Blake, based on git versions 2.62.*.
211 ** AC_C_BIGENDIAN does not mistakenly report "universal" for some
212 bigendian hosts, a regression introduced with universal binary
215 ** AC_PATH_X now includes /lib64 and /usr/lib64 in its list of default
218 ** AC_USE_SYSTEM_EXTENSIONS no longer conflicts with an external
219 AC_DEFINE([__EXTENSIONS__]). This fixes a regression introduced in
220 2.62 when using macros such as AC_AIX that were made obsolete in
221 favor of the more portable AC_USE_SYSTEM_EXTENSIONS.
223 ** AC_CHECK_TARGET_TOOLS is usable in the non-cross-compile case.
225 ** Newly obsolete macros
226 The following macro has been marked obsolete, since current porting
227 targets can safely assume C89 semantics that signal handlers return
228 void. We have no current plans to remove the macro.
232 ** The macros m4_map and m4_map_sep now ignore any list elements
233 consisting of just empty quotes, and m4_map_sep now expands its
234 separator. This fixes a regression in 2.62 when these macros were
235 first documented, for the sake of clients expecting the semantics
236 that these macros had prior to that time. The new macros m4_mapall
237 and m4_mapall_sep, along with extra quoting of the separator, can
238 be used to get the semantics that m4_map_sep had in 2.62.
240 ** Clients of m4_expand, such as AS_HELP_STRING and AT_SETUP, can now
241 handle properly quoted but otherwise unbalanced parentheses (for
242 some macros, this fixes a regression in 2.62).
244 ** Two new quadrigraphs have been introduced: @{:@ for (, and @:}@ for ),
245 allowing the output of unbalanced parentheses in more contexts.
247 ** The following m4sugar macros are new:
248 m4_cleardivert m4_joinall m4_mapall m4_mapall_sep m4_reverse
249 m4_set_add m4_set_add_all m4_set_contains m4_set_contents
250 m4_set_delete m4_set_difference m4_set_dump m4_set_empty
251 m4_set_foreach m4_set_intersection m4_set_list m4_set_listc
252 m4_set_remove m4_set_size m4_set_union
254 ** The following m4sugar macros now accept multiple arguments, as is the
255 case with underlying m4:
256 m4_defn m4_popdef m4_undefine
258 ** The following m4sugar macros now guarantee linear scaling; they
259 previously had linear scaling with m4 1.6 but quadratic scaling
260 when using m4 1.4.x. All macros built on top of these also gain
261 the scaling improvements.
262 m4_bmatch m4_bpatsubsts m4_case m4_cond m4_do m4_dquote_elt
263 m4_foreach m4_join m4_list_cmp m4_map m4_map_sep m4_max
266 ** AT_KEYWORDS once again performs expansion on its argument, such that
267 AT_KEYWORDS([m4_if([$1], [], [default])]) no longer complains about
268 the possibly unexpanded m4_if [regression introduced in 2.62].
270 ** Config header templates `#undef UNDEFINED /* comment */' do not lead to
271 nested comments any more; regression introduced in 2.62.
274 * Major changes in Autoconf 2.62 (2008-04-05) [stable]
275 Released by Eric Blake, based on git versions 2.61a.*.
277 ** Many optimizations have been applied to make overall execution faster.
279 ** Autotest now makes use of shell functions.
281 ** config.status now uses awk instead of sed also for config headers.
283 - As a side effect, AC_DEFINE and AC_DEFINE_UNQUOTED now handle multi-line
284 values, i.e., backslash-newline combinations are handled correctly.
285 Further, for config headers, the total size of values is not limited by
286 the POSIX length limit of text lines any more, only each single line.
288 ** New config variable `top_build_prefix'.
290 ** New Autoconf macros:
291 AC_AUTOCONF_VERSION AC_OPENMP AC_PATH_PROGS_FEATURE_CHECK
293 ** AC_C_BIGENDIAN now supports universal binaries a la Mac OS X.
295 ** AC_C_RESTRICT now prefers to #define 'restrict' to a variant spelling
296 like '__restrict' if the variant spelling is available, as this is
297 more likely to work when mixing C and C++ code.
299 ** AC_CHECK_ALIGNOF's type argument T is now documented better: it must
300 be a string of tokens such that "T y;" is a valid member declaration
303 ** AC_CHECK_SIZEOF now accepts objects as well as types: the general rule
304 is that sizeof (X) works, then AC_CHECK_SIZEOF (X) should work.
306 ** AC_CHECK_TYPE and AC_CHECK_TYPES now work on any C type-name; formerly,
307 they did not work for function types. In C++, they now work on any
308 type-id that can be the operand of sizeof; this is similar to C,
309 except it excludes anonymous struct and union types. Formerly,
310 some (but not all) C++ types involving anonymous struct and union
311 were accepted, though this was not documented.
313 ** AC_CONFIG_LINKS now prefers to link against files in the build tree
314 if found, and it works to link against a file of the same name in
315 the source tree, even if both trees coincide.
317 ** AC_INIT no longer alters $@; regression introduced in 2.60.
319 ** AC_USE_SYSTEM_EXTENSIONS now defines _ALL_SOURCE for Interix platforms.
321 ** AS_HELP_STRING no longer underquotes its first argument; it also handles
322 the case where the first argument contains single-quoted commas.
323 For example, "AS_HELP_STRING([-a, [--arg[=foo]]], [bar])" produces:
324 " -a, --arg[=foo] bar"
325 Additionally, the macro now takes two additional arguments,
326 indent-column and wrap-column; these should not normally be needed,
327 but can be used to fine-tune how the output text is wrapped.
329 ** AC_PROG_INSTALL now requires an install program that can install multiple
330 files into a target directory.
332 ** The command 'autoconf -' now correctly processes a file from stdin.
334 ** 'autoreconf -m' now honors $MAKE.
336 ** For all of the directory arguments for 'configure', such as '--prefix'
337 or '--bindir', trailing slashes are stripped. As an example, if
338 tab completion in the user's shell appends trailing slashes, the
339 command './configure --prefix=/usr/' will still result in an
340 expanded libdir value of /usr/lib, not /usr//lib.
342 ** `configure --help=recursive' now works in read-only trees and from
343 unconfigured build trees.
345 ** If precious variables differ only in whitespace, then the cache consistency
346 check warns instead of fails, and reuses the old value.
348 ** AT_BANNER is now documented.
350 ** AT_SETUP now handles macro expansions properly when calculating line
353 ** Autotest now determines $srcdir correctly.
355 ** Testsuites built by autotest now accept a -C/--directory=DIR option
356 to adjust the working directory prior to creating files.
358 ** Autoconf now requires GNU M4 1.4.5 or later. Earlier versions of M4 have
359 a bug in macro tracing that interferes with the interaction between
360 Autoconf and Automake. GNU M4 1.4.11 or later is recommended. The
361 configure search for a working M4 is improved.
363 ** For portability with the eventual M4 2.0, macros should no longer use
364 anything larger than $9 to refer to arguments.
366 ** Documentation for m4sugar is improved.
368 - The following macros were previously available as undocumented
369 interfaces; the macros are now documented as stable interfaces.
371 __oline__ m4_assert m4_bmatch m4_bpatsubsts m4_car m4_case
372 m4_cdr m4_default m4_divert_once m4_divert_pop m4_divert_push
373 m4_divert_text m4_do m4_errprintn m4_fatal m4_flatten
374 m4_ifndef m4_ifset m4_ifval m4_ifvaln m4_location
375 m4_n m4_shiftn m4_strip m4_warn
377 - The following macros were previously available as undocumented
378 interfaces, but had bug fixes or semantic changes as part of this
379 release. Packages that relied on the undocumented behavior
380 should be analyzed to make sure they will still work with the
381 new documented behavior.
383 m4_cmp m4_list_cmp m4_join m4_map m4_map_sep m4_sign
384 m4_text_box m4_text_wrap m4_version_compare
386 - The m4_wrap macro used to have unspecified order, but now
387 guarantees FIFO order. m4_wrap_lifo was added to guarantee LIFO
390 - Packages using the undocumented m4sugar macro m4_PACKAGE_VERSION
391 should consider using the new AC_AUTOCONF_VERSION instead.
393 - m4sugar macros that are not documented in the manual are still
394 deemed experimental, and should not be used outside of Autoconf.
396 ** The m4sugar macros m4_append and m4_append_uniq, first documented in
397 2.60, have been fixed to treat both the string and the separator
398 arguments consistently with regards to quoting. Prior to this fix,
399 m4_append_uniq could mistakenly duplicate entries if the expansion
400 of the separator resulted in a different string (for example, if it
401 contained quotes, a comma, or a macro name). However, it means
402 that programs previously using
403 m4_append([name], [string], [[, ]])
404 are now using a four-character separator instead of the intended
405 comma and space. If you need portability to earlier versions of
406 Autoconf, you can insert the following snippet after AC_INIT but
407 before any other macro expansions, to enforce the new semantics:
408 m4_pushdef([m4_append], [m4_define([$1],
409 m4_ifdef([$1], [m4_defn([$1])[$3]])[$2])])
410 Additionally, m4_append_uniq now takes optional parameters that can
411 be used to take action depending on whether anything was appended,
412 and warns if a non-empty separator occurs within the string being
413 appended, since that can lead to duplicates.
415 ** The following m4sugar macros are new:
416 m4_append_uniq_w m4_apply m4_combine m4_cond m4_count
417 m4_dquote_elt m4_echo m4_expand m4_ignore m4_make_list m4_max
418 m4_min m4_newline m4_shift2 m4_shift3 m4_unquote m4_wrap_lifo
420 ** Warnings are now generated by default when an installer invokes
421 'configure' with an unknown --enable-* or --with-* option.
422 These warnings can be disabled with the new AC_DISABLE_OPTION_CHECKING
423 macro, or by invoking 'configure' with --disable-option-checking.
425 ** Existing obsolete macros
426 The documentation for the following macros is adjusted to make it
427 more clear that they have previously been marked obsolete, as their
428 functionality can be accomplished by other macros. We have no
429 current plans to remove them from Autoconf.
431 AC_ENABLE AC_STRUCT_ST_BLKSIZE AC_STRUCT_ST_RDEV AC_WITH
433 ** Newly obsolete macros
434 The following macros have been marked obsolete, as they only
435 perform a subset of AC_USE_SYSTEM_EXTENSIONS. We have no current
436 plans to remove them.
438 AC_AIX AC_GNU_SOURCE AC_ISC_POSIX AC_MINIX
440 ** AC_C_LONG_DOUBLE is obsolescent.
441 The documentation now says that AC_C_LONG_DOUBLE is obsolescent: it
442 tests for problems that are so old that it is no longer of
443 practical importance on current systems. New programs need not use
444 AC_C_LONG_DOUBLE. We have no current plans to remove it.
446 ** AC_DIAGNOSE, AC_WARNING, and AC_FATAL are obsolescent.
447 The documentation now favors the use of M4sugar macros m4_warn and
448 m4_fatal, since the naming makes it more obvious that the
449 diagnostics are associated with M4 expansion (ie. when running
450 `autoconf'), and offers less confusion with the AC_MSG_ERROR,
451 AC_MSG_FAILURE, and AC_MSG_WARN macros which manage diagnostics
452 when running `configure'. We have no current plans to remove these
456 * Major changes in Autoconf 2.61a (2006-12-11)
458 ** AC_FUNC_FSEEKO was broken in 2.61; it didn't make fseeko and ftello visible
459 on many platforms. This has been fixed.
461 ** AC_FUNC_SETVBUF_REVERSED is now obsolete. It is still defined for backward
462 compatibility but it does nothing. The macro was already
463 obsolescent, as the last systems to have the problem were those
464 based on SVR2, which became obsolete in 1987. The macro had bugs
465 on some modern systems and could no longer be maintained reliably
466 due to lack of ancient systems to test it on.
468 ** config.status now uses awk instead of sed for most substitutions, for speed.
470 - As a side effect multi-line values of substituted variables no
471 longer have a small limit in total size, though for portability
472 each line should not exceed the POSIX length limit for text lines.
474 - It is now documented that Makefile.in should not contain
475 overlapping variable occurrences, e.g., @VAR1@VAR2@.
476 Autoconf's behavior was always iffy in such cases, and the
477 awk implementation has changed the behavior.
479 ** Many uses of 'echo' have been rewritten so that Autoconf-generated
480 scripts have fewer problems with strings or file names containing
481 embedded special characters such as backslash or leading "-". This
482 was implemented by using `printf '%s\n' "$foo"' instead of `echo
483 "$foo"' when printf works. Due to the implementation technique
484 used, Autoconf-generated scripts now run considerably more slowly
485 on ancient implementations lacking printf. However, this should
486 not be a problem, since Autoconf-generated scripts in practice
487 invariably find a more-modern shell these days.
490 * Major changes in Autoconf 2.61 (2006-11-17)
492 ** New macros AC_C_FLEXIBLE_ARRAY_MEMBER, AC_C_VARARRAYS.
494 ** AC_ARG_ENABLE and AC_ARG_WITH now allow '.' in feature and package names.
497 * Major changes in Autoconf 2.60b (2006-10-22)
500 Autoconf-generated shell scripts no longer export BIN_SH, due to
501 configuration hassles with this. Installers who need BIN_SH in
502 their environment should set it before invoking 'configure' and
503 'make'. As far as we know, this affects only Unixware installations.
505 ** Obsolescent macros
506 The documentation now says that the following macros are obsolescent,
507 as they are superseded by Gnulib:
509 AC_FUNC_FNMATCH AC_FUNC_FNMATCH_GNU AC_FUNC_GETLOADVG AC_REPLACE_FNMATCH
511 New programs should use the Gnulib counterparts of these macros.
512 We have no current plans to remove them from Autoconf.
514 ** AC_COMPUTE_INT no longer caches or reports results.
516 ** AC_CHECK_DECL now also works with aggregate objects.
518 ** AC_USE_SYSTEM_EXTENSIONS now defines _TANDEM_SOURCE for NonStop platforms.
520 ** GNU M4 1.4.7 or later is now recommended.
523 New M4sugar macro, which is more secure than the POSIX M4 maketemp.
526 Now an alias for m4_mkstemp.
528 * Major changes in Autoconf 2.60a (2006-08-25)
530 ** GNU M4 1.4.6 or later is now recommended.
532 ** The check for C99 now tests for varargs macros, as documented.
533 It also tests that the preprocessor supports 64-bit integers.
535 ** Autoconf now uses constructs like "#ifdef HAVE_STDLIB_H" rather than
536 "#if HAVE_STDLIB_H", so that it now works with "gcc -Wundef -Werror".
538 ** The functionality of the undocumented _AC_COMPUTE_INT is now provided
539 by a public and documented macro, AC_COMPUTE_INT. The parameters to the
540 two macros are different, so autoupdate will not change the old private name
541 to the new one. _AC_COMPUTE_INT may be removed in a future release.
543 ** AC_TYPE_LONG_LONG_INT and AC_TYPE_UNSIGNED_LONG_LONG_INT now require
544 that long long types be at least 64 bits wide, as C99 and tradition
545 requires. Formerly, they accepted implementations of any width.
548 * Major changes in Autoconf 2.60
550 Released 2006-06-23, by Ralf Wildenhues.
552 ** Autoconf no longer depends on whether m4wrap is FIFO (as Posix requires)
553 or LIFO (as in GNU M4 1.4.x). GNU M4 2.0 is expected to conform to Posix
554 here, so m4wrap/m4_wrap users should no longer depend on LIFO behavior.
556 ** Provide a way to turn off warnings about the changed directory variables.
558 * Major changes in Autoconf 2.59d
560 Released 2006-06-05, by Ralf Wildenhues.
562 ** GNU make now recommended for VPATH builds
563 INSTALL now suggests VPATH builds (e.g., "sh ../srcdir/configure")
564 only if you use GNU make. In practice, other 'make' implementations
565 have too many subtle incompatibilities in their support for VPATH.
566 Many packages (including Autoconf itself) are portable to other
567 'make' implementations, but some packages are not, and recommending
568 GNU make keeps the installation instructions simpler.
570 ** Even more safety checks for the new Directory variables:
571 Warn about suspicious `${datarootdir}' found in config files output.
573 ** AC_TRY_COMMAND, AC_TRY_EVAL, ac_config_guess, ac_config_sub, ac_configure
574 These never-documented macros and variables have been marked with
575 comments saying that they may be removed in a future release,
576 because their use can lead to unintended code being executed.
577 If you need functionality that only these macros or variables
578 currently supply, please write bug-autoconf@gnu.org.
580 ** AC_SUBST, AC_DEFINE
581 Literal arguments to these are passed to m4_pattern_allow now.
584 Passing 'ac_cv_prog_cc_stdc=no' to 'configure' now sets ac_cv_prog_cc_c99
585 and ac_cv_prog_cc_c89 to 'no' as well, for backward compatibility with
586 obsolete K&R tests in the Automake test suite.
595 Now more robust with special characters in file names, or when
596 multiple processes create the same directory at the same time.
598 ** Obsolescent macros
599 The documentation now says that the following macros are obsolescent:
600 they test for problems that are so old that they are no longer of
601 practical importance on current systems.
603 AC_C_BACKSLASH_A AC_FUNC_MEMCMP AC_HEADER_DIRENT
604 AC_C_CONST AC_FUNC_SELECT_ARGTYPES AC_HEADER_STAT
605 AC_C_PROTOTYPES AC_FUNC_SETPGRP AC_HEADER_STDC
606 AC_C_STRINGIZE AC_FUNC_SETVBUF_REVERSED AC_HEADER_SYS_WAIT
607 AC_C_VOLATILE AC_FUNC_STAT AC_HEADER_TIME
608 AC_FUNC_CLOSEDIR_VOID AC_FUNC_STRFTIME AC_ISC_POSIX
609 AC_FUNC_GETPGRP AC_FUNC_UTIME_NULL AC_PROG_GCC_TRADITIONAL
610 AC_FUNC_LSTAT AC_FUNC_VPRINTF AC_STRUCT_TM
612 New programs need not use these macros. We have no current plans to
616 For compatibility with future Libtool 2.0, autoreconf will invoke
617 libtoolize with the option `--ltdl' now, if LT_CONFIG_LTDL_DIR is
620 * Major changes in Autoconf 2.59c
622 Released 2006-04-12, by Ralf Wildenhues.
624 ** The configure command now redirects standard input from /dev/null,
625 to help avoid problems with subsidiary commands that might mistakenly
626 read standard input. AS_ORIGINAL_STDIN_FD points to the original
627 standard input before this redirection, if you really want configure to
628 read from standard input.
630 ** Directory variables adjusted to recent changes in the GNU Coding Standards.
631 The following directory variables are new:
633 datarootdir read-only architecture-independent data root [PREFIX/share]
634 localedir locale-specific message catalogs [DATAROOTDIR/locale]
635 docdir documentation root [DATAROOTDIR/doc/PACKAGE]
636 htmldir html documentation [DOCDIR]
637 dvidir dvi documentation [DOCDIR]
638 pdfdir pdf documentation [DOCDIR]
639 psdir ps documentation [DOCDIR]
641 The following variables have new default values:
643 datadir read-only architecture-independent data [DATAROOTDIR]
644 infodir info documentation [DATAROOTDIR/info]
645 mandir man documentation [DATAROOTDIR/man]
647 This means that if you use any of `@datadir@', `@infodir@', or
648 `@mandir@' in a file, you will have to ensure `${datarootdir}' is
649 defined in this file. As a temporary measure, if any of those are
650 found but no mention of `datarootdir', the substitutions will be
651 replaced with values that do not contain `${datarootdir}', and a
652 warning will be issued.
654 ** @top_builddir@ is now a dir name: it is always nonempty and doesn't have
655 a trailing slash. Similar change will be made to ac_top_builddir in a
656 future release; the old style value, which matches (../)*, is (and will
657 continue to be) available as ac_top_build_prefix.
660 New macro to check for support of 'typeof' syntax a la GNU C.
662 ** AC_CHECK_DECLS_ONCE, AC_CHECK_FUNCS_ONCE, AC_CHECK_HEADERS_ONCE
663 New "once-only" variants of commonly-used macros, to make 'configure'
664 smaller and faster in common cases.
667 New macro to check for strtold with C99 semantics.
670 New macro that lets builder disable assertions at 'configure'-time.
673 Now checks for X11/Xlib.h and XrmInitialize (X proper) rather than
674 X11/Intrinsic.h and XtMalloc (Xt).
676 ** AC_PRESERVE_HELP_ORDER
677 New macro that causes `configure' to display help strings for AC_ARG_ENABLE
678 and AC_ARG_WITH arguments in one region, in the order defined. The default
679 behavior is to group options of each classes separately.
681 ** AC_PROG_CC, AC_PROG_CXX
682 No longer automatically arrange to declare the 'exit' function of C,
683 when a C++ compiler is used. Standard Autoconf macros no longer use
684 'exit', so this is no longer an issue for them. If you use C++, and
685 want to call 'exit', you'll have to arrange for its declaration
686 yourself. But we now suggest you return from 'main' instead.
688 ** AC_PROG_CC_C89, AC_PROG_CC_C99
689 New macros for ISO C99 support. AC_PROG_CC_C89 and AC_PROG_CC_C99
690 check for ANSI C89 and ISO C99 support respectively.
693 Has been unobsoleted, and will check if the compiler supports ISO
694 C99, falling back to ANSI C89 if not. ac_cv_prog_cc_stdc is
695 retained for backwards compatibility, assuming the value of
696 ac_cv_prog_cc_c99 or ac_cv_prog_cc_c89 (whichever is valid, in
699 ** AC_STRUCT_DIRENT_D_INO, AC_STRUCT_DIRENT_D_TYPE
700 New macros for checking commonly-used members of struct dirent.
703 The substituted value can now contain newlines.
706 The substitution now occurs only when @variable@ is on a line by itself,
707 optionally surrounded by spaces and tabs. The whole line is replaced.
709 ** AC_TYPE_LONG_DOUBLE, AC_TYPE_LONG_DOUBLE_WIDER
710 New macros to check for long double, and whether it is wider than double.
711 The old macro AC_C_TYPE_LONG_DOUBLE has been marked as obsolete;
712 applications should switch to the new macro.
714 ** AC_TYPE_INT8_T, AC_TYPE_INT16_T, AC_TYPE_INT32_T, AC_TYPE_INT64_T,
715 AC_TYPE_INTMAX_T, AC_TYPE_INTPTR_T, AC_TYPE_LONG_LONG_INT, AC_TYPE_SSIZE_T,
716 AC_TYPE_UINT8_T, AC_TYPE_UINT16_T, AC_TYPE_UINT32_T, AC_TYPE_UINT64_T,
717 AC_TYPE_UINTMAX_T, AC_TYPE_UINTPTR_T, AC_TYPE_UNSIGNED_LONG_LONG_INT
718 New macros to check for C99 and POSIX types.
720 ** AC_USE_SYSTEM_EXTENSIONS
721 New macro to enable extensions to Posix.
724 New macro which is defined to the name of the first declared config header
725 or undefined if no config headers have been declared yet.
728 The macro correctly handles quadrigraphs now.
730 ** AS_BOURNE_COMPATIBLE, AS_SHELL_SANITIZE, AS_CASE
731 These macros are new or published now.
734 New macro for copyright notices in testsuite files.
736 ** ALLOCA, LIBOBJS, LTLIBOBJS
737 Object names added to these variables are now prefixed with `${LIBOBJDIR}',
738 as in `${LIBOBJDIR}alloca.o'. LIBOBJDIR is meant to be defined from
739 `Makefile.in' in case the object files lie in a different directory.
740 The LIBOBJDIR feature is experimental.
743 Supports --no-recursive now.
745 ** New macros to support Erlang/OTP.
746 New macros for configuring paths to Erlang tools and libraries:
747 AC_ERLANG_PATH_ERLC, AC_ERLANG_NEED_ERLC, AC_ERLANG_PATH_ERL,
748 AC_ERLANG_NEED_ERL, AC_ERLANG_CHECK_LIB, AC_ERLANG_SUBST_ROOT_DIR,
749 AC_ERLANG_SUBST_LIB_DIR.
751 New macros for configuring installation of Erlang libraries:
752 AC_ERLANG_SUBST_INSTALL_LIB_DIR, AC_ERLANG_SUBST_INSTALL_LIB_SUBDIR.
754 ** The manual now mentions Gnulib more prominently.
756 ** New macros to support Objective C.
757 AC_PROG_OBJC, AC_PROG_OBJCPP.
759 * Major changes in Autoconf 2.59b
761 Released 2004-08-20, by Paul Eggert.
764 New macro that computes the default alignment of a type.
766 ** AC_CHECK_TOOL, AC_PATH_TOOL, AC_CHECK_TOOLS
767 When cross-compiling, these macros will give a warning if the tool
768 is not prefixed. In the future, unprefixed cross tools will not
769 be detected; please consult the info documentation for information
770 about the reason of this change.
772 ** AC_CHECK_TARGET_TOOL, AC_PATH_TARGET_TOOL, AC_CHECK_TARGET_TOOLS
773 New macros that detect programs whose name is prefixed with the
774 target type, if the build type and target type are different.
776 ** AC_REQUIRE_AUX_FILE
777 New trace macro that declares expected auxiliary files.
780 New macro that tests for a grep program that accepts as a long a line
783 ** AC_PROG_EGREP, AC_PROG_FGREP
784 These macros now require AC_PROG_GREP, and try EGREP="$GREP -E" and
785 FGREP="$GREP -F" respectively if possible, or else run a path search for
786 a program that accepts as long a line as possible.
789 New macro that tests for a sed program that truncates as few characters
792 * Major changes in Autoconf 2.59
794 Released 2003-11-04, by Akim Demaille
796 ** ac_abs_builddir etc.
797 Absolute file names were actually relative in 2.58.
799 * Major changes in Autoconf 2.58
801 Released 2003-11-04, by Akim Demaille
804 core.* files are no longer removed, as they may be valid user files.
806 ** autoreconf and auxiliary directory
807 Autoreconf creates the auxiliary directory if needed. This is
808 especially useful for initial "bootstrapping" of fresh CVS checkouts.
810 ** AC_CONFIG_MACRO_DIR
811 Use this macro to declare the directory for local M4 macros for aclocal.
814 No longer includes twice the same file in LIBOBJS if invoked
817 ** AC_CONFIG_COMMANDS
818 The directory for its first argument is automatically created. For
821 AC_CONFIG_COMMANDS([src/modules.hh], [...])
823 $top_builddir/src/ is created if needed.
825 ** Autotest and local.at
826 The optional file local.at is always included in Autotest test suites.
829 The warnings are always issued, including with cached runs.
830 This became a significant problem since aclocal and automake can
831 run autoconf behind the scene.
833 ** autoheader warnings
834 The warnings of autoheader can be turned off, using --warning.
835 For instance, -Wno-obsolete disables the complaints about acconfig.h
836 and other deprecated constructs.
839 AC_C_RESTRICT, AC_INCLUDES_DEFAULT, AC_LANG_ASSERT, AC_LANG_WERROR,
842 ** AC_DECL_SYS_SIGLIST
846 Now checks that mktime is the inverse of localtime.
848 ** Improve DJGPP portability
849 The Autoconf tools and configure behave better under DJGPP.
851 ** Present But Cannot Be Compiled
852 New FAQ section dedicated to the mystic
854 configure: WARNING: pi.h: present but cannot be compiled
855 configure: WARNING: pi.h: check for missing prerequisite headers?
856 configure: WARNING: pi.h: proceeding with the preprocessor's result
859 ** Concurrent executions of autom4te
860 autom4te now locks its internal files, which enables concurrent
861 executions of autom4te, likely to happen if automake, autoconf,
862 autoheader etc. are run simultaneously.
865 Use of Libtool 1.5 and higher is encouraged. Compatibility with
866 Libtool pre-1.4 is not checked.
869 Testsuites no longer rerun failed tests in verbose mode; instead,
870 failures are logged while the test is run.
872 In addition, expected failures can be marked as such.
874 * Major changes in Autoconf 2.57
876 Released 2002-12-03 by Paul Eggert.
878 Bug fixes for problems with AIX linker, with freestanding C compilers,
879 with GNU M4 limitations, and with obsolete copies of GNU documents.
881 The Free Documentation License has been upgraded from 1.1 to 1.2.
883 * Major changes in Autoconf 2.56
885 Released 2002-11-15 by Akim Demaille.
887 One packaging problem fixed (config/install-sh was not executable).
889 * Major changes in Autoconf 2.55
891 Released 2002-11-14 by Akim Demaille.
895 Have your configure.ac checked by autoscan ("autoscan").
896 Try the warning options ("autoreconf -fv -Wall").
900 - AC_CHECK_HEADER, AC_CHECK_HEADERS
901 More information on proper use.
903 - Writing Test Programs
905 This sections explains how to write good test sources to use with
906 AC_COMPILE_IFELSE etc. It documents AC_LANG_PROGRAM and so forth.
908 - AC_FOO_IFELSE vs. AC_TRY_FOO
910 Explains why Autoconf moves from AC_TRY_COMPILE etc. to
911 AC_COMPILE_IFELSE and AC_LANG_PROGRAM etc.
915 - Is more robust to different Gettext installations.
917 - Produces messages (when --verbose) to be understood by Emacs'
920 - Supports -W/--warnings.
923 Once the GNU Build System reinstalled, run `./config.status
924 --recheck && ./config.status && make' if possible.
928 - Supports --cache, and --no-cache.
930 - ~/.autom4te.cfg makes it possible to disable the caching mechanism
931 (autom4te.cache). See `Customizing autom4te' in the documentation.
938 Support for the obsoleted options -m, --macrodir, -l, --localdir is
939 dropped in favor of the safer --include/--prepend-include scheme.
944 AC_COMPILER_IFELSE, AC_FUNC_MBRTOWC, AC_HEADER_STDBOOL,
945 AC_LANG_CONFTEST, AC_LANG_SOURCE, AC_LANG_PROGRAM, AC_LANG_CALL,
946 AC_LANG_FUNC_TRY_LINK, AC_MSG_FAILURE, AC_PREPROC_IFELSE.
949 Obsoleted macros are kept for Autoconf backward compatibility, but
950 should be avoided in configure.ac. Running autoupdate is advised.
953 - AC_DEFINE/AC_DEFINE_UNQUOTED
955 We have to stop using the old compatibility scheme --that tried to
956 avoid useless backslashes-- because Libtool 1.4.3 contains a
958 AC_DEFINE([error_t], [int],
959 [Define to a type to use for \`error_t' if it is not
960 otherwise available.])
962 We have to quote the single quotes and backslashes with \. The old
963 compatibility scheme saw that ` was backslashed, and therefore did
964 not quote the single quote... Failure. Hence, Autoconf 2.54 is not
965 compatible with Libtool. Autoconf 2.55 is, but in some cases might
966 produce more \ than wanted.
968 Please, note that in the future the same problem will happen with
969 AC_MSG_*: use `autoreconf -f -Wall'.
973 - Portability of the Autoconf package to Solaris.
975 - Spurious warnings caused by config.status.
976 This bug is benign, but painful: on some systems (typically
977 FreeBSD), warnings such as:
979 config.status: creating Makefile
980 mv: Makefile: set owner/group (was: 1357/0): Operation not permitted
982 could be issued. This is fixed.
985 Simultaneous executions of config.status are possible again.
987 - Precious variables accumulation
989 config.status could stack several copies of the precious variables
993 ** Plans for later versions
997 The compatibility hooks with the old scheme will be completely
998 removed. Please, advice/use `--build', `--host', and `--target'
1001 - AC_CHECK_HEADER, AC_CHECK_HEADERS
1003 The tests will be stricter, please make sure your invocations are
1008 Shell functions will gradually be introduced, probably starting with
1009 Autotest. If you know machines which are in use that you suspect
1010 *not* to support shell functions, please run the test suite of
1011 Autoconf 2.55 on it, and report the results to
1012 bug-autoconf@gnu.org.
1016 Special characters in AC_MSG_* need not be quoted. Currently,
1017 Autoconf has heuristics to decide when a string is escaped, or has
1018 to be escaped. This scheme is fragile, and will be removed; the
1019 only risk is uglified messages. Please, run `autoreconf -f -Wall'
1020 to find occurrences that will be affected.
1022 * Major changes in Autoconf 2.54
1024 Released 2002-09-13 by Akim Demaille.
1028 - autoreconf no longer changes the version of the gettext/po/intl
1029 support files. It now adds the files the correspond to the
1030 AM_GNU_GETTEXT_VERSION declared in configure.ac.
1032 Warning: It now relies on the 'autopoint' program, which is part
1033 of GNU gettext 0.11.4 and newer.
1035 Please note that you need to have a GNU gettext version that
1036 corresponds at least to the AM_GNU_GETTEXT_VERSION declared
1037 in configure.ac. You can upgrade to newer GNU gettext versions,
1038 though, without needing to change configure.ac.
1040 - The -I DIR or --include=DIR option now appends DIR to the include path
1041 instead of prepending; this is for consistency with other GNU tools.
1042 The new -B DIR or --prepend-include=DIR option has the old behavior.
1047 Now handles all the gory details about LIBOBJS and LTLIBOBJS.
1048 Please, remove lines such as
1050 # This is necessary so that .o files in LIBOBJS are also
1051 # built via the ANSI2KNR-filtering rules.
1052 LIBOBJS=`echo $LIBOBJS|sed 's/\.o /\$U.o /g;s/\.o$/\$U.o/'`
1054 and read the `AC_LIBOBJ vs LIBOBJS' section. Do not define U in
1055 your Makefiles either.
1057 - AC_CONFIG_LINKS now makes copies if it can't make links.
1059 - AC_FUNC_FNMATCH now tests only for POSIX compatibility, reverting to
1060 Autoconf 2.13 behavior. The new macro AC_FUNC_FNMATCH_GNU also
1061 tests for GNU extensions to fnmatch, and replaces fnmatch if needed.
1063 - AC_FUNC_SETVBUF_REVERSED no longer fails when cross-compiling.
1065 - AC_PROG_CC_STDC is integrated into AC_PROG_CC.
1067 - AC_PROG_F77 default search no longer includes cf77 and cfg77.
1071 AC_C_BACKSLASH_A, AC_CONFIG_LIBOBJ_DIR, AC_GNU_SOURCE,
1072 AC_PROG_EGREP, AC_PROG_FGREP, AC_REPLACE_FNMATCH,
1073 AC_FUNC_FNMATCH_GNU, AC_FUNC_REALLOC, AC_TYPE_MBSTATE_T.
1075 - AC_FUNC_GETLOADAVG
1076 looks for getloadavg.c in the CONFIG_LIBOBJ_DIR.
1079 Now defines HAVE_MALLOC to 0 if `malloc' does not work, and asks
1080 for an AC_LIBOBJ replacement.
1084 - Spurious complaints from `m4_bmatch' about invalid regular
1085 expressions are suppressed.
1087 - Empty top_builddirs are properly handled.
1089 - AC_CHECK_MEMBER works correctly when the member is an aggregate.
1092 Now colon in the optional path arguments are properly handled.
1094 ** Improved portability
1096 - Both Autoconf the package, and the scripts it produces, should run
1097 more reliably with Zsh. Bear in mind it is the default Bourne shell
1100 - Autoconf and the scripts it produces no longer assume the existence of
1101 the obsolescent commands egrep and fgrep.
1105 - Limitations of Make
1109 The GNATS base moved to
1110 http://bugs.gnu.org/cgi-bin/gnatsweb.pl?database=autoconf
1111 (It is no longer available, though.)
1116 Now contains the list of ouput variables and files (AC_SUBST,
1119 * Major changes in Autoconf 2.53
1121 Released 2002-03-08 by Akim Demaille.
1125 Perl 5.005_03 or later is required: autom4te is written in Perl and is
1126 needed by autoconf. autoheader, autoreconf, ifnames, and autoscan are
1132 Argument requirements, output variables, defined macros.
1133 - M4sugar, M4sh, Autotest
1135 - Double quoting macros
1136 AC_TRY_CPP, AC_TRY_COMPILE, AC_TRY_LINK and AC_TRY_RUN.
1138 The Autoconf manual is now distributed under the terms of the GNU FDL.
1139 - Section `Hosts and Cross-Compilation'
1140 Explains the rationale for the 2.5x changes in the cross-compilation
1141 chain, and in the relationships between build, host, and target
1143 Emphasizes that `cross-compilation' == `--host is given'.
1144 If you are working on compilers etc., be sure to read this section.
1145 - Section `AC_LIBOBJ vs. LIBOBJS'
1146 Explains why assigning LIBOBJS directly is now an error.
1147 Details how to update the code.
1152 Now used instead of hard coded line numbers.
1153 This eases the comparison of `configure's, and diminishes the
1154 pressure over control version archives.
1155 Automatic replacement for shells that don't support this feature.
1156 - New output variables
1157 @builddir@, @top_builddir@, @abs_srcdir@, @abs_top_srcdir@, @abs_builddir@,
1162 Autoconf and Autotest modes are provided.
1167 New, used by the Autoconf suite to cache and speed up most processing.
1169 Supported by autom4te, autoconf and autoheader.
1171 Replaces --autoconf-dir and --localdir in autoconf, autoheader,
1172 autoupdate, and autoreconf.
1174 No longer passes --cygnus, --foreign, --gnits, --gnu, --include-deps:
1175 automake options are to be given via AUTOMAKE_OPTIONS.
1177 Runs gettextize and libtoolize when appropriate.
1179 --m4dir is no longer supported.
1181 Now runs only in the specified directories, defaulting to `.',
1182 but understands AC_CONFIG_SUBDIRS for dependent directories.
1183 Before, it used to run on all the `configure.ac' found in the
1185 Independent packages are properly updated.
1189 - The top level $prefix is propagated to the AC_CONFIG_SUBDIRS configures.
1191 Under the user pressure, $? is finally available. Probably a mistake.
1192 - AC_F77_LIBRARY_LDFLAGS now supports the HP/UX f90 compiler.
1193 - Precious variables accumulation
1194 config.status could stack several copies of the precious variables
1196 - AC_PATH_PROG and family.
1197 Works properly when given a literal path.
1199 Somewhere since 2.13, the result had been reversed.
1203 - AC_C_BIGENDIAN supports the cross-compiling case.
1204 - AC_C_BIGENDIAN accepts ACTION-IF-TRUE, ACTION-IF-FALSE, and
1205 ACTION-IF-UNKNOWN arguments. All are facultative, and the default
1206 for ACTION-IF-TRUE is to define WORDS_BIGENDIAN like AC_C_BIGENDIAN
1208 - AC_C_LONG_DOUBLE now succeeds only if `long double' has more range or
1209 precision than `double'.
1214 It now defines the preprocessor symbols PACKAGE_NAME,
1215 PACKAGE_TARNAME, PACKAGE_VERSION, PACKAGE_STRING, and
1219 Admits a fourth optional parameter: the tar name.
1221 - AC_CONFIG_COMMANDS, HEADERS, FILES, LINKS.
1222 Provide the user with srcdir, ac_srcdir, ac_top_srcdir, ac_builddir,
1223 ac_top_builddir, ac_abs_srcdir, ac_abs_top_srcdir, ac_abs_builddir,
1224 ac_abs_top_builddir.
1226 - AC_CONFIG_COMMANDS, HEADERS, FILES, LINKS and AC_OUTPUT.
1227 Are much less expensive when using long lists of files.
1230 Works with shell variables, and non alphanumeric names.
1234 - AC_FUNC_STRERROR_R now sets STRERROR_R_CHAR_P, not HAVE_WORKING_STRERROR_R,
1235 because POSIX 1003.1-200x draft 7 says strerror_r returns int, not char *.
1237 - AC_FUNC_STRTOD substitutes POW_LIB.
1242 * Major changes in Autoconf 2.52
1244 Released 2001-07-18 by Akim Demaille.
1249 This feature was present in autoconf 2.50 but was not documented.
1250 For example, `@<:@' is translated to `[' just before output. This
1251 is useful when writing strings that contain unbalanced quotes, or
1252 other hard-to-quote constructs.
1253 - m4_pattern_forbid, m4_pattern_allow
1254 - Tips for upgrading from 2.13.
1255 - Using autoscan to maintain a configure.ac.
1258 - Now include stdint.h.
1259 - sys/types.h and sys/stat.h are guarded.
1260 - strings.h is included if available, and not conflicting with string.h.
1263 - The test suite is more robust and presents less false failures.
1264 - Invocation of GNU M4 now robust to POSIXLY_CORRECT.
1265 - configure accepts --prefix='' again.
1266 - AC_CHECK_LIB works properly when its first argument is not a
1268 - HAVE_INTTYPES_H is defined only if not conflicting with sys/types.h.
1269 - build_, host_, and target_alias are AC_SUBST as in 2.13.
1270 - AC_ARG_VAR properly propagates precious variables inherited from the
1271 environment to ./config.status.
1272 - Using --program-suffix/--program-prefix is portable.
1273 - Failures to detect the default compiler's output extension are less
1275 - `config.status foo' works properly when `foo' depends on variables
1276 set in an AC_CONFIG_THING INIT-CMD.
1277 - autoheader is more robust to broken input.
1278 - Fixed Fortran name-mangling and link tests on a number of systems,
1279 e.g. NetBSD; see AC_F77_DUMMY_MAIN, below.
1282 - AC_CHECK_HEADER and AC_CHECK_HEADERS support a fourth argument to
1283 specify pre-includes. In this case, the headers are compiled with
1284 cc, not merely preprocessed by cpp. Therefore it is the _usability_
1285 of a header which is checked for, not just its availability.
1286 - AC_ARG_VAR refuses to run configure when precious variables have
1288 - Versions of compilers are dumped in the logs.
1289 - AC_CHECK_TYPE recognizes use of `foo_t' as a replacement type.
1292 - AC_PATH_XTRA only adds -ldnet to $LIBS if it's needed to link.
1293 - AC_FUNC_WAIT3 and AC_SYS_RESTARTABLE_SYSCALLS are obsoleted.
1294 - AM_FUNC_ERROR_AT_LINE, AM_FUNC_FNMATCH, AM_FUNC_MKTIME,
1295 AM_FUNC_OBSTACK, and AM_FUNC_STRTOD are now activated.
1296 Be sure to read `Upgrading from Version 2.13' to understand why
1297 running `autoupdate' is needed.
1298 - AC_F77_DUMMY_MAIN, AC_F77_MAIN: new macros to detect whether
1299 a main-like routine is required/possible when linking C/C++ with
1300 Fortran. Users of e.g. AC_F77_WRAPPERS should be aware of these.
1301 - AC_FUNC_GETPGRG behaves better when cross-compiling.
1303 * Major changes in Autoconf 2.51
1304 There was no release of Autoconf 2.51 since some packagers had used
1305 this version number without permission to ship intermediary versions
1306 of 2.50. The version was skipped to avoid confusion.
1308 * Major changes in Autoconf 2.50
1310 Released 2001-05-21 by Akim Demaille.
1312 ** Lots of bug fixes
1313 There have been far too many to enumerate them here. Check out
1314 ChangeLog if you really want to know more.
1316 ** Improved documentation
1317 In particular, portability issues are better covered.
1320 All the standard GNU Makefile targets are supported. The layout has
1321 changed: m4/ holds the M4 extensions Autoconf needs for its
1322 configuration, doc/ contains the documentation, and tests/ contains
1325 ** Man pages are provided
1326 For autoconf, autoreconf, autoupdate, autoheader, autoscan, ifnames,
1327 config.guess, config.sub.
1331 Provides a safe and powerful means to trace the macro uses. This
1332 provide the parsing layer for tools which need to `study'
1336 Specify what category of warnings should be enabled.
1338 - When recursing into subdirectories, try for configure.gnu before
1339 configure to adapt for packages not using autoconf on case-insensitive
1343 More errors are now caught (circular AC_REQUIRE dependencies,
1344 AC_DEFINE in the action part of an AC_CACHE_CHECK, too many pops
1345 etc.). In addition, their location and call stack are given.
1348 autoupdate is much more powerful, and is able to provide the glue code
1349 which might be needed to move from an old macro to its newer
1352 You are strongly encouraged to use it to modernize both your
1353 `configure.in' and your .m4 extension files.
1356 The internal machinery of autoheader has completely changed. As a
1357 result, using `acconfig.h' should be considered to be obsoleted, and
1358 you are encouraged to get rid of it using the AH macros.
1363 ** Fortran 77 compilers
1364 Globally, the support for Fortran 77 is considerably improved.
1366 Support for automatically determining a Fortran 77 compiler's
1367 name-mangling scheme. New CPP macros F77_FUNC and F77_FUNC_ are
1368 provided to wrap C/C++ identifiers, thus making it easier and more
1369 transparent for C/C++ to call Fortran 77 routines, and Fortran 77 to
1370 call C/C++ routines. See the Texinfo documentation for details.
1373 The test suite no longer uses DejaGNU. It should be easy to submit
1374 test cases in this new framework.
1377 - --help, --help=long, -hl
1378 no longer dumps useless items.
1380 lists only specific options.
1381 - --help=recursive, -hr
1382 displays the help of all the embedded packages.
1383 - Remembers environment variables when reconfiguring.
1384 The previous scheme to set envvar before running configure was
1386 what prevented configure from remembering the environment in which
1387 it was run, therefore --recheck was run in an inconsistent
1388 environment. Now, one should run
1390 and then --recheck will work properly. Variables declared with
1391 AC_ARG_VAR are also preserved.
1393 $build defaults to `config.guess`, $host to $build, and then $target
1395 Cross-compilation is a global status of the package, it no longer
1396 depends upon the current language.
1397 Cross compilation is enabled iff the user specified `--host'.
1398 `configure' now fails if it can't run the executables it compiles,
1399 unless cross-compilation is enabled.
1401 The cache file is disabled by default. The new options
1402 `--config-cache', `-C' set the cache to `config.cache'.
1406 Much faster on most architectures.
1407 - concurrent executions
1408 It is safe to use `make -j' with config.status.
1409 - human interface improved
1410 It is possible to invoke
1411 ./config.status foobar
1412 instead of the former form (still valid)
1413 CONFIG_COMMANDS= CONFIG_HEADERS= CONFIG_LINKS= \
1414 CONFIG_FILES=foobar:foo.in:bar.in \
1416 The same holds for configuration headers and links.
1417 You can instantiate unknown files and headers:
1418 ./config.status --header foo.h:foo.h.in --file bar:baz
1419 - has a useful --help
1420 - accepts special file name "-" for stdin/stdout
1425 Specify additional copyright information.
1428 Now expects the identity of the package as argument.
1432 Most macros, if not all, now strictly follow the `one quotation
1433 level' rule. This results in a more predictable expansion.
1436 A sly bug in the AC_REQUIRE machinery, which could produce incorrect
1437 configure scripts, was fixed by Axel Thimm.
1441 Document and ask for the registration of an envvar.
1444 Specifies the file which `configure' should look for when trying to
1445 find the source tree (used to be handled by AC_INIT).
1447 - AC_CONFIG_COMMANDS
1448 To add new actions to config.status. Should be used instead of
1452 Replaces AC_LINK_FILES.
1454 - AC_CONFIG_HEADERS, AC_CONFIG_COMMANDS, AC_CONFIG_SUBDIRS,
1455 AC_CONFIG_LINKS, and AC_CONFIG_FILES
1456 They now obey sh: you should no longer use shell variables as
1457 argument. Instead of
1459 test "$package_foo_enabled" = yes && $my_subdirs="$my_subdirs foo"
1460 AC_CONFIG_SUBDIRS($my_subdirs)
1464 if test "$package_foo_enabled" = yes; then
1465 AC_CONFIG_SUBDIRS(foo)
1469 To format an Autoconf macro's help string so that it looks pretty
1470 when the user executes `configure --help'.
1473 ** Generic Test Macros
1475 The interface of the AC_CHECK families of macros (decl, header,
1476 type, member, func) is now uniform. They support the same set of
1479 - AC_CHECK_DECL, AC_CHECK_DECLS
1480 To check whether a symbol is declared.
1482 - AC_CHECK_SIZEOF, AC_C_CHAR_UNSIGNED.
1483 No longer need a cross-compilation default.
1486 The test it performs is much more robust than previously, and makes
1487 it possible to test builtin types in addition to typedefs.
1488 It is now schizophrenic:
1489 - AC_CHECK_TYPE(TYPE, REPLACEMENT)
1490 remains for backward compatibility, but its use is discouraged.
1491 - AC_CHECK_TYPE(TYPE, IF-FOUND, IF-NOT-FOUND, INCLUDES)
1492 behaves exactly like the other AC_CHECK macros.
1495 Checks whether given types are supported by the system.
1497 - AC_CHECK_MEMBER, AC_CHECK_MEMBERS
1498 Check for given members in aggregates (e.g., pw_gecos in struct
1502 Checks if the compiler supports ISO C, included when needs special
1506 Checking whether the preprocessor indicates missing includes by the
1507 error code. stderr is checked by AC_TRY_CPP only as a fallback.
1510 Takes a language as argument and replaces AC_LANG_C,
1511 AC_LANG_CPLUSPLUS and AC_LANG_FORTRAN77.
1513 - AC_LANG_PUSH, AC_LANG_POP
1514 Are preferred to AC_LANG_SAVE, AC_LANG_RESTORE.
1517 - AC_FUNC_CHOWN, AC_FUNC_MALLOC, AC_FUNC_STRERROR_R,
1518 AC_FUNC_LSTAT_FOLLOWS_SLASHED_SYMLINK, AC_FUNC_STAT, AC_FUNC_LSTAT,
1519 AC_FUNC_ERROR_AT_LINE, AC_FUNC_OBSTACK, AC_FUNC_STRTOD, AC_FUNC_FSEEKO.
1523 Sets GETGROUPS_LIBS.
1525 - AC_FUNC_GETLOADAVG
1526 Defines `HAVE_STRUCT_NLIST_N_UN_N_NAME' instead of `NLIST_NAME_UNION'.
1529 Now integrates `AC_DECL_YYTEXT' which is obsoleted.
1532 Arrange for large-file support.
1534 - AC_EXEEXT, AC_OBJEXT
1535 You are no longer expected to use them: their computation is
1536 performed by default.
1538 ** C++ compatibility
1539 Every macro has been revisited in order to support at best CC=c++.
1541 Major changes in Autoconf 2.14:
1542 There was no release of GNU Autoconf 2.14.
1544 Major changes in Autoconf 2.13:
1546 Released 1999-05-01 by Ben Elliston.
1548 * Support for building on Win32 systems where the only available C or
1549 C++ compiler is the Microsoft Visual C++ command line compiler
1550 (`cl'). Additional support for building on Win32 systems which are
1551 using the Cygwin or Mingw32 environments.
1552 * Support for alternative object file and executable file extensions.
1553 On Win32, for example, these are .obj and .exe. These are discovered
1554 using AC_OBJEXT and AC_EXEEXT, which substitute @OBJEXT@ and
1555 @EXEEXT@ in the output, respectively.
1556 * New macros: AC_CACHE_LOAD, AC_CACHE_SAVE, AC_FUNC_SELECT_ARGTYPES,
1557 AC_VALIDATE_CACHED_SYSTEM_TUPLE, AC_SEARCH_LIBS, AC_TRY_LINK_FUNC,
1558 AC_C_STRINGIZE, AC_CHECK_FILE(S), AC_PROG_F77 (and friends).
1559 * AC_DEFINE now has an optional third argument for a description to be
1560 placed in the config header input file (e.g. config.h.in).
1561 * The C++ code fragment compiled for the C++ compiler test had to be
1562 improved to include an explicit return type for main(). This was
1563 causing failures on systems using recent versions of the EGCS C++
1565 * Fixed an important bug in AC_CHECK_TYPE that would cause a configure
1566 script to report that `sometype_t' was present when only `type_t'
1568 * Merge of the FSF version of config.guess and config.sub to modernize
1569 these scripts. Add support for a few new hosts in config.guess.
1570 Incorporate latest versions of install-sh, mkinstalldirs and
1571 texinfo.tex from the FSF.
1572 * autoreconf is capable of running automake if necessary (and
1574 * Support for Fortran 77. See the Texinfo documentation for details.
1575 * Bug fixes and workarounds for quirky bugs in vendor utilities.
1577 Major changes in Autoconf 2.12:
1579 Released 1996-11-26 by David J. MacKenzie
1581 * AC_OUTPUT and AC_CONFIG_HEADER can create output files by
1582 concatenating multiple input files separated by colons, like so:
1583 AC_CONFIG_HEADER(config.h:conf.pre:config.h.in:conf.post)
1584 AC_OUTPUT(Makefile:Makefile.in:Makefile.rules)
1585 The arguments may be shell variables, to compute the lists on the fly.
1586 * AC_LINK_FILES and AC_CONFIG_SUBDIRS may be called multiple times.
1587 * New macro AC_OUTPUT_COMMANDS adds more commands to run in config.status.
1590 Major changes in Autoconf 2.11:
1592 Released November 18th, 1996, by David J. MacKenzie
1594 * AC_PROG_CC and AC_PROG_CXX check whether the compiler works.
1595 They also default CFLAGS/CXXFLAGS to "-g -O2" for gcc, instead of "-g -O".
1596 * AC_REPLACE_FUNCS defines HAVE_foo if the system has the function `foo'.
1597 * AC_CONFIG_HEADER expands shell variables in its argument.
1598 * New macros: AC_FUNC_FNMATCH, AC_FUNC_SETPGRP.
1599 * The "checking..." messages and the source code for test programs that
1600 fail are saved in config.log.
1601 * Another workaround has been added for seds with small command length limits.
1602 * config.sub and config.guess recognize more system types.
1605 Major changes in Autoconf 2.10:
1607 Released May 7th, 1996, by Roland McGrath
1610 * The cache variable names used by `AC_CHECK_LIB(LIB, FUNC, ...)' has
1611 changed: now $ac_cv_lib_LIB_FUNC, previously $ac_cv_lib_LIB.
1613 Major changes in Autoconf 2.9:
1615 Released March 16th, 1996, by Roland McGrath
1619 Major changes in Autoconf 2.8:
1621 Released March 8th, 1996, by Roland McGrath
1625 Major changes in Autoconf 2.7:
1627 Released November 22nd, 1995, by David J. MacKenzie
1631 Major changes in Autoconf 2.6:
1633 Released November 20th, 1995, by David J. MacKenzie
1637 Major changes in Autoconf 2.5:
1639 Released November 17th, 1995, by Roland McGrath
1641 * New configure options --bindir, --libdir, --datadir, etc., with
1642 corresponding output variables.
1643 * New macro: AC_CACHE_CHECK, to make using the cache easier.
1644 * config.log contains the command being run as well as any output from it.
1645 * AC_CHECK_LIB can check for libraries with "." or "/" or "+" in their name.
1646 * AC_PROG_INSTALL doesn't cache a name for install-sh, for sharing caches.
1647 * AC_CHECK_PROG, AC_PATH_PROG, AC_CHECK_PROGS, AC_PATH_PROGS, and
1648 AC_CHECK_TOOL can search a path other than $PATH.
1649 * AC_CHECK_SIZEOF takes an optional size to use when cross-compiling.
1651 Major changes in Autoconf 2.4:
1653 Released June 14th, 1995, by David J. MacKenzie
1655 * Fix a few bugs found by Emacs testers.
1657 Major changes in Autoconf 2.3:
1659 Released March 27th, 1995, by David J. MacKenzie
1661 * Fix the cleanup trap in several ways.
1662 * Handle C compilers that are picky about option placement.
1663 * ifnames gets the version number from the right directory.
1665 Major changes in Autoconf 2.2:
1667 Released March 8th, 1995, by David J. MacKenzie
1669 * The ifnames utility is much faster but requires a "new awk" interpreter.
1670 * AC_CHECK_LIB and AC_HAVE_LIBRARY check and add the new
1671 library before existing libs, not after, in case it uses them.
1672 * New macros: AC_FUNC_GETPGRP, AC_CHECK_TOOL.
1673 * Lots of bug fixes.
1674 * Many additions to the TODO file :-)
1676 Major changes in Autoconf 2.1:
1678 Released November 4th, 1994, by David J. MacKenzie
1681 * More explanations in the manual.
1682 * Fix a spurious failure in the testsuite.
1683 * Clarify some warning messages.
1684 * autoreconf by default only rebuilds configure and config.h.in files
1685 that are older than any of their particular input files; there is a
1686 --force option to use after installing a new version of Autoconf.
1688 Thanks to everybody who's submitted changes and additions to Autoconf!
1689 I've incorporated many of them, and am still considering others for
1690 future releases -- but I didn't want to postpone this release indefinitely.
1692 Caution: don't indiscriminately rebuild configure scripts with
1693 Autoconf version 2. Some configure.in files need minor adjustments to
1694 work with it; the documentation has a chapter on upgrading. A few
1695 configure.in files, including those for GNU Emacs and the GNU C
1696 Library, need major changes because they relied on undocumented
1697 internals of version 1. Future releases of those packages will have
1698 updated configure.in files.
1700 It's best to use GNU M4 1.3 (or later) with Autoconf version 2.
1701 Autoconf now makes heavy use of M4 diversions, which were implemented
1702 inefficiently in GNU M4 releases before 1.3.
1704 Major changes in Autoconf 2.0:
1706 Released October 26th, 1994, by David J. MacKenzie
1708 ** New copyright terms:
1709 * There are no restrictions on distribution or use of configure scripts.
1712 * Autoconf manual is reorganized to make information easier to find
1713 and has several new indexes.
1714 * INSTALL is reorganized and clearer and is now made from Texinfo source.
1717 * autoscan to generate a preliminary configure.in for a package by
1718 scanning its source code for commonly used nonportable functions,
1719 programs, and header files.
1720 * ifnames to list the symbols used in #if and #ifdef directives in a
1722 * autoupdate to update a configure.in to use the version 2 macro names.
1723 * autoreconf to recursively remake configure and configuration header
1724 files in a source tree.
1726 ** Changed utilities:
1727 * autoheader can take pieces of acconfig.h to replace config.h.{top,bot}.
1728 * autoconf and autoheader can look for package-local definition files
1729 in an alternate directory.
1732 * AC_CACHE_VAL to share results of tests between configure runs.
1733 * AC_DEFUN to define macros, automatically AC_PROVIDE them, and ensure
1734 that macros invoked with AC_REQUIRE don't interrupt other macros.
1735 * AC_CONFIG_AUX_DIR, AC_CANONICAL_SYSTEM, AC_CANONICAL_HOST, AC_LINK_FILES to
1736 support deciding unguessable features based on the host and target types.
1737 * AC_CONFIG_SUBDIRS to recursively configure a source tree.
1738 * AC_ARG_PROGRAM to use the options --program-prefix,
1739 --program-suffix, and --program-transform-name to change the names
1740 of programs being installed.
1741 * AC_PREFIX_DEFAULT to change the default installation prefix.
1742 * AC_TRY_COMPILE to compile a test program without linking it.
1743 * AC_CHECK_TYPE to check whether sys/types.h or stdlib.h defines a given type.
1744 * AC_CHECK_LIB to check for a particular function and library.
1745 * AC_MSG_CHECKING and AC_MSG_RESULT to print test results, on a single line,
1746 whether or not the test succeeds. They obsolete AC_CHECKING and AC_VERBOSE.
1747 * AC_SUBST_FILE to insert one file into another.
1748 * AC_FUNC_MEMCMP to check whether memcmp is 8-bit clean.
1749 * AC_FUNC_STRFTIME to find strftime even if it's in -lintl.
1750 * AC_FUNC_GETMNTENT to find getmntent even if it's in -lsun or -lseq.
1751 * AC_HEADER_SYS_WAIT to check whether sys/wait.h is POSIX.1 compatible.
1754 * Many macros renamed systematically, but old names are accepted for
1755 backward compatibility.
1756 * AC_OUTPUT adds the "automatically generated" comment to
1757 non-Makefiles where it finds @configure_input@ in an input file, to
1758 support files with various comment syntaxes.
1759 * AC_OUTPUT does not replace "prefix" and "exec_prefix" in generated
1760 files when they are not enclosed in @ signs.
1761 * AC_OUTPUT allows the optional environment variable CONFIG_STATUS to
1762 override the file name "config.status".
1763 * AC_OUTPUT takes an optional argument for passing variables from
1764 configure to config.status.
1765 * AC_OUTPUT and AC_CONFIG_HEADER allow you to override the input-file names.
1766 * AC_OUTPUT automatically substitutes the values of CFLAGS, CXXFLAGS,
1767 CPPFLAGS, and LDFLAGS from the environment.
1768 * AC_PROG_CC and AC_PROG_CXX now set CFLAGS and CXXFLAGS, respectively.
1769 * AC_PROG_INSTALL looks for install-sh or install.sh in the directory
1770 specified by AC_CONFIG_AUXDIR, or srcdir or srcdir/.. or
1771 srcdir/../.. by default.
1772 * AC_DEFINE, AC_DEFINE_UNQUOTED, and AC_SUBST are more robust and smaller.
1773 * AC_DEFINE no longer prints anything, because of the new result reporting
1774 mechanism (AC_MSG_CHECKING and AC_MSG_RESULT).
1775 * AC_VERBOSE pays attention to --quiet/--silent, not --verbose.
1776 * AC_ARG_ENABLE and AC_ARG_WITH support whitespace in the arguments to
1777 --enable- and --with- options.
1778 * AC_CHECK_FUNCS and AC_CHECK_HEADERS take optional shell commands to
1779 execute on success or failure.
1780 * Checking for C functions in C++ works.
1783 * AC_REMOTE_TAPE and AC_RSH removed; too specific to tar and cpio, and
1784 better maintained with them.
1785 * AC_ARG_ARRAY removed because no one was likely using it.
1786 * AC_HAVE_POUNDBANG replaced with AC_SYS_INTERPRETER, which doesn't
1787 take arguments, for consistency with all of the other specific checks.
1790 * Comes with config.sub and config.guess, and uses them optionally.
1791 * Uses config.cache to cache test results. An alternate cache file
1792 can be selected with the --cache-file=FILE option.
1793 * Uses optional shell scripts $prefix/share/config.site and
1794 $prefix/etc/config.site to perform site or system specific initializations.
1795 * configure saves compiler output to ./config.log for debugging.
1796 * New files autoconf.m4 and autoheader.m4 load the other Autoconf macros.
1797 * acsite.m4 is the new name for the system-wide aclocal.m4.
1798 * Has a DejaGnu test suite.
1800 Major changes in Autoconf 1.11:
1802 * AC_PROG_INSTALL calls install.sh with the -c option.
1803 * AC_SET_MAKE cleans up after itself.
1804 * AC_OUTPUT sets prefix and exec_prefix if they weren't set already.
1805 * AC_OUTPUT prevents shells from looking in PATH for config.status.
1807 Plus a few other bug fixes.
1809 Major changes in Autoconf 1.10:
1811 * autoheader uses config.h.bot if present, analogous to config.h.top.
1812 * AC_PROG_INSTALL looks for install.sh in srcdir or srcdir/.. and
1814 * AC_PROG_CXX looks for cxx as a C++ compiler.
1816 Plus several bugs fixed.
1818 Major changes in Autoconf 1.9:
1820 * AC_YYTEXT_POINTER replaces AC_DECLARE_YYTEXT.
1821 * AC_SIZEOF_TYPE generates the cpp symbol name automatically,
1822 and autoheader generates entries for those names automatically.
1823 * AC_FIND_X gets the result from xmkmf correctly.
1824 * AC_FIND_X assumes no X if --without-x was given.
1825 * AC_FIND_XTRA adds libraries to the variable X_EXTRA_LIBS.
1826 * AC_PROG_INSTALL finds OSF/1 installbsd.
1828 Major changes in Autoconf 1.8:
1831 * New macros AC_LANG_C, AC_LANG_CPLUSPLUS, AC_LANG_SAVE, AC_LANG_RESTORE,
1832 AC_PROG_CXX, AC_PROG_CXXCPP, AC_REQUIRE_CPP
1833 for checking both C++ and C features in one configure script.
1834 * New macros AC_CHECKING, AC_VERBOSE, AC_WARN, AC_ERROR for printing messages.
1835 * New macros AC_FIND_XTRA, AC_MMAP, AC_SIZEOF_TYPE, AC_PREREQ,
1836 AC_SET_MAKE, AC_ENABLE.
1839 * AC_FIND_X looks for X in more places.
1840 * AC_PROG_INSTALL defaults to install.sh instead of cp, if it's in srcdir.
1841 install.sh is distributed with Autoconf.
1842 * AC_DECLARE_YYTEXT has been removed because it can't work, pending
1843 a rewrite of quoting in AC_DEFINE.
1844 * AC_OUTPUT adds its comments in C format when substituting in C files.
1845 * AC_COMPILE_CHECK protects its ECHO-TEXT argument with double quotes.
1847 ** New or changed command line options:
1848 * configure accepts --enable-FEATURE[=ARG] and --disable-FEATURE options.
1849 * configure accepts --without-PACKAGE, which sets withval=no.
1850 * configure accepts --x-includes=DIR and --x-libraries=DIR.
1851 * Giving --with-PACKAGE no argument sets withval=yes instead of withval=1.
1852 * configure accepts --help, --version, --silent/--quiet, --no-create options.
1853 * configure accepts and ignores most other Cygnus configure options, and
1854 warns about unknown options.
1855 * config.status accepts --help, --version options.
1857 ** File names and other changes:
1858 * Relative srcdir values are not made absolute.
1859 * The values of @prefix@ and @exec_prefix@ and @top_srcdir@ get substituted.
1860 * Autoconf library files are installed in ${datadir}/autoconf, not ${datadir}.
1861 * autoheader optionally copies config.h.top to the beginning of config.h.in.
1862 * The example Makefile dependencies for configure et al. work better.
1863 * Namespace cleanup: all shell variables used internally by Autoconf
1864 have names beginning with `ac_'.
1866 More big improvements are in process for future releases, but have not
1867 yet been (variously) finished, integrated, tested, or documented enough
1870 Major changes in Autoconf 1.7:
1872 * New macro AC_OBSOLETE.
1873 * Bugs in Makefile.in fixed.
1874 * AC_LONG_FILE_NAMES improved.
1876 Major changes in Autoconf 1.6:
1878 * New macro AC_LONG_64_BITS.
1879 * Multiple .h files can be created.
1880 * AC_FIND_X looks for X files directly if it doesn't find xmkmf.
1881 * AC_ALLOCA defines C_ALLOCA if using alloca.c.
1882 * --with-NAME can take a value, e.g., --with-targets=sun4,hp300bsd.
1883 * Unused --no-create option to configure removed.
1884 * autoheader doesn't change the timestamp of its output file if
1885 the file didn't change.
1886 * All macros that look for libraries now use AC_HAVE_LIBRARY.
1887 * config.status checks three optional environment variables to
1888 modify its behavior.
1889 * The usual bug fixes.
1891 Major changes in Autoconf 1.5:
1893 * New macros AC_FIND_X, AC_OFF_T, AC_STAT_MACROS_BROKEN, AC_REVISION.
1894 * autoconf and autoheader scripts have GNU standards conforming
1895 --version and --help options (they print their message and exit).
1898 Major changes in Autoconf 1.4:
1900 * New macros AC_HAVE_POUNDBANG, AC_TIME_WITH_SYS_TIME, AC_LONG_DOUBLE,
1901 AC_GETGROUPS_T, AC_DEFINE_UNQUOTED.
1902 * autoconf and autoheader use the M4 environment variable to determine the
1903 name of the M4 program to use.
1904 * The --macrodir option to autoconf and autoheader specifies the directory
1905 in which acspecific.m4, acgeneral.m4, etc. reside if not the default.
1906 * autoconf and autoheader can take `-' as their file names, which means to
1907 read stdin as input.
1908 * Resulting configure scripts can take a --verbose option which causes them
1909 to print the results of their tests.
1910 * AC_DEFINE quotes its second argument in such a way that spaces, magic
1911 shell characters, etc. will be preserved during various stages of
1912 expansion done by the shell. If you don't want this, use
1913 AC_DEFINE_UNQUOTED instead.
1914 * Much textual processing done with external calls to tr and sed have been
1915 internalized with builtin M4 `patsubst' and `translit' calls.
1916 * AC_OUTPUT doesn't hardwire the file names it outputs. Instead, you can
1917 set the shell variables `gen_files' and `gen_config' to the list of
1918 file names to output.
1919 * AC_DECLARE_YYTEXT does an AC_SUBST of `LEX_OUTPUT_ROOT', which may be
1920 "lex.yy" or "lexyy", depending on the system.
1921 * AC_PROGRAMS_CHECK takes an optional third arg. If given, it is used as
1923 * If AC_ALLOCA chooses alloca.c, it also defines STACK_DIRECTION.
1924 * AC_CONST works much more reliably on more systems.
1927 Major changes in Autoconf 1.3:
1929 configure no longer requires awk for packages that use a config.h.
1930 Support handling --with-PACKAGE options.
1931 New `autoheader' script to create `config.h.in' from `configure.in'.
1932 Ignore troublesome -lucb and -lPW when searching for alloca.
1933 Rename --exec_prefix to --exec-prefix for GNU standards conformance.
1934 Improve detection of STDC library.
1935 Add AC_HAVE_LIBRARY to check for non-default libraries.
1936 Function checking should work with future GNU libc releases.
1938 Major changes in Autoconf 1.2:
1940 The --srcdir option is now usually unnecessary.
1941 Add a file containing sample comments describing CPP macros.
1942 A comment in config.status tells which host it was configured on.
1943 Substituted variable values can now contain commas.
1944 Fix bugs in various feature checks.
1946 Major changes in Autoconf 1.1:
1948 Added AC_STRCOLL macro.
1949 Made AC_GETLOADAVG check for more things.
1950 AC_OUTPUT argument is now optional.
1955 Copyright (C) 1993, 1994, 1995, 1996, 1998, 1999, 2000, 2001, 2002,
1956 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 Free Software Foundation,
1959 Copying and distribution of this file, with or without modification,
1960 are permitted in any medium without royalty provided the copyright
1961 notice and this notice are preserved. This file is offered as-is,
1962 without warranty of any kind.