liblzma: Prevent uninitialzed warning in mt stream encoder.
[xz/debian.git] / configure.ac
blob9ab921e149e8870fc300dd7c04ee05dd2ebb7374
1 #                                               -*- Autoconf -*-
2 # Process this file with autoconf to produce a configure script.
4 ###############################################################################
6 # Author: Lasse Collin
8 # This file has been put into the public domain.
9 # You can do whatever you want with this file.
11 ###############################################################################
13 # NOTE: Don't add useless checks. autoscan detects this and that, but don't
14 # let it confuse you. For example, we don't care about checking for behavior
15 # of malloc(), stat(), or lstat(), since we don't use those functions in
16 # a way that would cause the problems the autoconf macros check.
18 AC_PREREQ([2.69])
20 AC_INIT([XZ Utils], m4_esyscmd([/bin/sh build-aux/version.sh]),
21         [xz@tukaani.org], [xz], [https://tukaani.org/xz/])
22 AC_CONFIG_SRCDIR([src/liblzma/common/common.h])
23 AC_CONFIG_AUX_DIR([build-aux])
24 AC_CONFIG_MACRO_DIR([m4])
25 AC_CONFIG_HEADERS([config.h])
27 echo
28 echo "$PACKAGE_STRING"
30 echo
31 echo "System type:"
32 # This is needed to know if assembler optimizations can be used.
33 AC_CANONICAL_HOST
35 # We do some special things on Windows (32-bit or 64-bit) builds.
36 case $host_os in
37         mingw* | cygwin | msys) is_w32=yes ;;
38         *)                      is_w32=no ;;
39 esac
40 AM_CONDITIONAL([COND_W32], [test "$is_w32" = yes])
42 # We need to use $EXEEXT with $(LN_S) when creating symlinks to
43 # executables. Cygwin is an exception to this, since it is recommended
44 # that symlinks don't have the .exe suffix. To make this work, we
45 # define LN_EXEEXT.
47 # MSYS2 is treated the same way as Cygwin. It uses plain "msys" like
48 # the original MSYS when building MSYS/MSYS2-binaries. Hopefully this
49 # doesn't break things for the original MSYS developers. Note that this
50 # doesn't affect normal MSYS/MSYS2 users building non-MSYS/MSYS2 binaries
51 # since in that case the $host_os is usually mingw32.
52 case $host_os in
53         cygwin | msys)  LN_EXEEXT= ;;
54         *)              LN_EXEEXT='$(EXEEXT)' ;;
55 esac
56 AC_SUBST([LN_EXEEXT])
58 echo
59 echo "Configure options:"
60 AM_CFLAGS=
63 #############
64 # Debugging #
65 #############
67 AC_MSG_CHECKING([if debugging code should be compiled])
68 AC_ARG_ENABLE([debug], AS_HELP_STRING([--enable-debug], [Enable debugging code.]),
69         [], enable_debug=no)
70 if test "x$enable_debug" = xyes; then
71         AC_MSG_RESULT([yes])
72 else
73         AC_DEFINE([NDEBUG], [1], [Define to 1 to disable debugging code.])
74         AC_MSG_RESULT([no])
78 ###########
79 # Filters #
80 ###########
82 m4_define([SUPPORTED_FILTERS], [lzma1,lzma2,delta,x86,powerpc,ia64,arm,armthumb,arm64,sparc])dnl
83 m4_define([SIMPLE_FILTERS], [x86,powerpc,ia64,arm,armthumb,arm64,sparc])
84 m4_define([LZ_FILTERS], [lzma1,lzma2])
86 m4_foreach([NAME], [SUPPORTED_FILTERS],
87 [enable_filter_[]NAME=no
88 enable_encoder_[]NAME=no
89 enable_decoder_[]NAME=no
90 ])dnl
92 AC_MSG_CHECKING([which encoders to build])
93 AC_ARG_ENABLE([encoders], AS_HELP_STRING([--enable-encoders=LIST],
94                 [Comma-separated list of encoders to build. Default=all.
95                 Available encoders:]
96                         m4_translit(m4_defn([SUPPORTED_FILTERS]), [,], [ ])),
97         [], [enable_encoders=SUPPORTED_FILTERS])
98 enable_encoders=`echo "$enable_encoders" | sed 's/,/ /g'`
99 if test "x$enable_encoders" = xno || test "x$enable_encoders" = x; then
100         enable_encoders=no
101         AC_MSG_RESULT([(none)])
102 else
103         for arg in $enable_encoders
104         do
105                 case $arg in m4_foreach([NAME], [SUPPORTED_FILTERS], [
106                         NAME)
107                                 enable_filter_[]NAME=yes
108                                 enable_encoder_[]NAME=yes
109                                 AC_DEFINE(HAVE_ENCODER_[]m4_toupper(NAME), [1],
110                                 [Define to 1 if] NAME [encoder is enabled.])
111                                 ;;])
112                         *)
113                                 AC_MSG_RESULT([])
114                                 AC_MSG_ERROR([unknown filter: $arg])
115                                 ;;
116                 esac
117         done
118         AC_DEFINE([HAVE_ENCODERS], [1],
119                 [Define to 1 if any of HAVE_ENCODER_foo have been defined.])
120         AC_MSG_RESULT([$enable_encoders])
123 AC_MSG_CHECKING([which decoders to build])
124 AC_ARG_ENABLE([decoders], AS_HELP_STRING([--enable-decoders=LIST],
125                 [Comma-separated list of decoders to build. Default=all.
126                 Available decoders are the same as available encoders.]),
127         [], [enable_decoders=SUPPORTED_FILTERS])
128 enable_decoders=`echo "$enable_decoders" | sed 's/,/ /g'`
129 if test "x$enable_decoders" = xno || test "x$enable_decoders" = x; then
130         enable_decoders=no
131         AC_MSG_RESULT([(none)])
132 else
133         for arg in $enable_decoders
134         do
135                 case $arg in m4_foreach([NAME], [SUPPORTED_FILTERS], [
136                         NAME)
137                                 enable_filter_[]NAME=yes
138                                 enable_decoder_[]NAME=yes
139                                 AC_DEFINE(HAVE_DECODER_[]m4_toupper(NAME), [1],
140                                 [Define to 1 if] NAME [decoder is enabled.])
141                                 ;;])
142                         *)
143                                 AC_MSG_RESULT([])
144                                 AC_MSG_ERROR([unknown filter: $arg])
145                                 ;;
146                 esac
147         done
148         AC_DEFINE([HAVE_DECODERS], [1],
149                 [Define to 1 if any of HAVE_DECODER_foo have been defined.])
150         AC_MSG_RESULT([$enable_decoders])
153 if test "x$enable_encoder_lzma2$enable_encoder_lzma1" = xyesno \
154                 || test "x$enable_decoder_lzma2$enable_decoder_lzma1" = xyesno; then
155         AC_MSG_ERROR([LZMA2 requires that LZMA1 is also enabled.])
158 AM_CONDITIONAL(COND_MAIN_ENCODER, test "x$enable_encoders" != xno)
159 AM_CONDITIONAL(COND_MAIN_DECODER, test "x$enable_decoders" != xno)
161 m4_foreach([NAME], [SUPPORTED_FILTERS],
162 [AM_CONDITIONAL(COND_FILTER_[]m4_toupper(NAME), test "x$enable_filter_[]NAME" = xyes)
163 AM_CONDITIONAL(COND_ENCODER_[]m4_toupper(NAME), test "x$enable_encoder_[]NAME" = xyes)
164 AM_CONDITIONAL(COND_DECODER_[]m4_toupper(NAME), test "x$enable_decoder_[]NAME" = xyes)
165 ])dnl
167 # The so called "simple filters" share common code.
168 enable_filter_simple=no
169 enable_encoder_simple=no
170 enable_decoder_simple=no
171 m4_foreach([NAME], [SIMPLE_FILTERS],
172 [test "x$enable_filter_[]NAME" = xyes && enable_filter_simple=yes
173 test "x$enable_encoder_[]NAME" = xyes && enable_encoder_simple=yes
174 test "x$enable_decoder_[]NAME" = xyes && enable_decoder_simple=yes
175 ])dnl
176 AM_CONDITIONAL(COND_FILTER_SIMPLE, test "x$enable_filter_simple" = xyes)
177 AM_CONDITIONAL(COND_ENCODER_SIMPLE, test "x$enable_encoder_simple" = xyes)
178 AM_CONDITIONAL(COND_DECODER_SIMPLE, test "x$enable_decoder_simple" = xyes)
180 # LZ-based filters share common code.
181 enable_filter_lz=no
182 enable_encoder_lz=no
183 enable_decoder_lz=no
184 m4_foreach([NAME], [LZ_FILTERS],
185 [test "x$enable_filter_[]NAME" = xyes && enable_filter_lz=yes
186 test "x$enable_encoder_[]NAME" = xyes && enable_encoder_lz=yes
187 test "x$enable_decoder_[]NAME" = xyes && enable_decoder_lz=yes
188 ])dnl
189 AM_CONDITIONAL(COND_FILTER_LZ, test "x$enable_filter_lz" = xyes)
190 AM_CONDITIONAL(COND_ENCODER_LZ, test "x$enable_encoder_lz" = xyes)
191 AM_CONDITIONAL(COND_DECODER_LZ, test "x$enable_decoder_lz" = xyes)
194 #################
195 # Match finders #
196 #################
198 m4_define([SUPPORTED_MATCH_FINDERS], [hc3,hc4,bt2,bt3,bt4])
200 m4_foreach([NAME], [SUPPORTED_MATCH_FINDERS],
201 [enable_match_finder_[]NAME=no
204 AC_MSG_CHECKING([which match finders to build])
205 AC_ARG_ENABLE([match-finders], AS_HELP_STRING([--enable-match-finders=LIST],
206                 [Comma-separated list of match finders to build. Default=all.
207                 At least one match finder is required for encoding with
208                 the LZMA1 and LZMA2 filters. Available match finders:]
209                 m4_translit(m4_defn([SUPPORTED_MATCH_FINDERS]), [,], [ ])), [],
210         [enable_match_finders=SUPPORTED_MATCH_FINDERS])
211 enable_match_finders=`echo "$enable_match_finders" | sed 's/,/ /g'`
212 if test "x$enable_encoder_lz" = xyes ; then
213         if test -z "$enable_match_finders"; then
214                 AC_MSG_ERROR([At least one match finder is required for an LZ-based encoder.])
215         fi
217         for arg in $enable_match_finders
218                 do
219                 case $arg in m4_foreach([NAME], [SUPPORTED_MATCH_FINDERS], [
220                         NAME)
221                                 enable_match_finder_[]NAME=yes
222                                 AC_DEFINE(HAVE_MF_[]m4_toupper(NAME), [1],
223                                 [Define to 1 to enable] NAME [match finder.])
224                                 ;;])
225                         *)
226                                 AC_MSG_RESULT([])
227                                 AC_MSG_ERROR([unknown match finder: $arg])
228                                 ;;
229                 esac
230         done
231         AC_MSG_RESULT([$enable_match_finders])
232 else
233         AC_MSG_RESULT([(none because not building any LZ-based encoder)])
237 ####################
238 # Integrity checks #
239 ####################
241 m4_define([SUPPORTED_CHECKS], [crc32,crc64,sha256])
243 m4_foreach([NAME], [SUPPORTED_CHECKS],
244 [enable_check_[]NAME=no
245 ])dnl
247 AC_MSG_CHECKING([which integrity checks to build])
248 AC_ARG_ENABLE([checks], AS_HELP_STRING([--enable-checks=LIST],
249                 [Comma-separated list of integrity checks to build.
250                 Default=all. Available integrity checks:]
251                 m4_translit(m4_defn([SUPPORTED_CHECKS]), [,], [ ])),
252         [], [enable_checks=SUPPORTED_CHECKS])
253 enable_checks=`echo "$enable_checks" | sed 's/,/ /g'`
254 if test "x$enable_checks" = xno || test "x$enable_checks" = x; then
255         AC_MSG_RESULT([(none)])
256 else
257         for arg in $enable_checks
258         do
259                 case $arg in m4_foreach([NAME], [SUPPORTED_CHECKS], [
260                         NAME)
261                                 enable_check_[]NAME=yes
262                                 AC_DEFINE(HAVE_CHECK_[]m4_toupper(NAME), [1],
263                                 [Define to 1 if] NAME
264                                 [integrity check is enabled.])
265                                 ;;])
266                         *)
267                                 AC_MSG_RESULT([])
268                                 AC_MSG_ERROR([unknown integrity check: $arg])
269                                 ;;
270                 esac
271         done
272         AC_MSG_RESULT([$enable_checks])
274 if test "x$enable_check_crc32" = xno ; then
275         AC_MSG_ERROR([For now, the CRC32 check must always be enabled.])
278 m4_foreach([NAME], [SUPPORTED_CHECKS],
279 [AM_CONDITIONAL(COND_CHECK_[]m4_toupper(NAME), test "x$enable_check_[]NAME" = xyes)
280 ])dnl
282 AC_MSG_CHECKING([if external SHA-256 should be used])
283 AC_ARG_ENABLE([external-sha256], AS_HELP_STRING([--enable-external-sha256],
284                 [Use SHA-256 code from the operating system.
285                 See INSTALL for possible subtle problems.]),
286                 [], [enable_external_sha256=no])
287 if test "x$enable_check_sha256" != "xyes"; then
288         enable_external_sha256=no
290 if test "x$enable_external_sha256" = xyes; then
291         AC_MSG_RESULT([yes])
292 else
293         AC_MSG_RESULT([no])
297 #############
298 # MicroLZMA #
299 #############
301 AC_MSG_CHECKING([if MicroLZMA support should be built])
302 AC_ARG_ENABLE([microlzma], AS_HELP_STRING([--disable-microlzma],
303                 [Do not build MicroLZMA encoder and decoder.
304                 It is needed by specific applications only,
305                 for example, erofs-utils.]),
306         [], [enable_microlzma=yes])
307 case $enable_microlzma in
308         yes | no)
309                 AC_MSG_RESULT([$enable_microlzma])
310                 ;;
311         *)
312                 AC_MSG_RESULT([])
313                 AC_MSG_ERROR([--enable-microlzma accepts only `yes' or `no'.])
314                 ;;
315 esac
316 AM_CONDITIONAL(COND_MICROLZMA, test "x$enable_microlzma" = xyes)
319 #############################
320 # .lz (lzip) format support #
321 #############################
323 AC_MSG_CHECKING([if .lz (lzip) decompression support should be built])
324 AC_ARG_ENABLE([lzip-decoder], AS_HELP_STRING([--disable-lzip-decoder],
325                 [Disable decompression support for .lz (lzip) files.]),
326         [], [enable_lzip_decoder=yes])
327 if test "x$enable_decoder_lzma1" != xyes; then
328         enable_lzip_decoder=no
329         AC_MSG_RESULT([no because LZMA1 decoder is disabled])
330 elif test "x$enable_lzip_decoder" = xyes; then
331         AC_DEFINE([HAVE_LZIP_DECODER], [1],
332                 [Define to 1 if .lz (lzip) decompression support is enabled.])
333         AC_MSG_RESULT([yes])
334 else
335         AC_MSG_RESULT([no])
337 AM_CONDITIONAL(COND_LZIP_DECODER, test "x$enable_lzip_decoder" = xyes)
340 ###########################
341 # Assembler optimizations #
342 ###########################
344 AC_MSG_CHECKING([if assembler optimizations should be used])
345 AC_ARG_ENABLE([assembler], AS_HELP_STRING([--disable-assembler],
346                 [Do not use assembler optimizations even if such exist
347                 for the architecture.]),
348         [], [enable_assembler=yes])
349 if test "x$enable_assembler" = xyes; then
350         enable_assembler=no
351         case $host_os in
352                 # Darwin should work too but only if not creating universal
353                 # binaries. Solaris x86 could work too but I cannot test.
354                 linux* | *bsd* | mingw* | cygwin | msys | *djgpp*)
355                         case $host_cpu in
356                                 i?86)   enable_assembler=x86 ;;
357                         esac
358                         ;;
359         esac
361 case $enable_assembler in
362         x86 | no)
363                 AC_MSG_RESULT([$enable_assembler])
364                 ;;
365         *)
366                 AC_MSG_RESULT([])
367                 AC_MSG_ERROR([--enable-assembler accepts only `yes', `no', or `x86' (32-bit).])
368                 ;;
369 esac
370 AM_CONDITIONAL(COND_ASM_X86, test "x$enable_assembler" = xx86)
373 #############
374 # CLMUL CRC #
375 #############
377 AC_ARG_ENABLE([clmul-crc], AS_HELP_STRING([--disable-clmul-crc],
378                 [Do not use carryless multiplication for CRC calculation
379                 even if support for it is detected.]),
380         [], [enable_clmul_crc=yes])
383 #####################
384 # Size optimization #
385 #####################
387 AC_MSG_CHECKING([if small size is preferred over speed])
388 AC_ARG_ENABLE([small], AS_HELP_STRING([--enable-small],
389                 [Make liblzma smaller and a little slower.
390                 This is disabled by default to optimize for speed.]),
391         [], [enable_small=no])
392 if test "x$enable_small" = xyes; then
393         AC_DEFINE([HAVE_SMALL], [1], [Define to 1 if optimizing for size.])
394 elif test "x$enable_small" != xno; then
395         AC_MSG_RESULT([])
396         AC_MSG_ERROR([--enable-small accepts only `yes' or `no'])
398 AC_MSG_RESULT([$enable_small])
399 AM_CONDITIONAL(COND_SMALL, test "x$enable_small" = xyes)
402 #############
403 # Threading #
404 #############
406 AC_MSG_CHECKING([if threading support is wanted])
407 AC_ARG_ENABLE([threads], AS_HELP_STRING([--enable-threads=METHOD],
408                 [Supported METHODS are `yes', `no', `posix', `win95', and
409                 `vista'. The default is `yes'. Using `no' together with
410                 --enable-small makes liblzma thread unsafe.]),
411         [], [enable_threads=yes])
413 if test "x$enable_threads" = xyes; then
414         case $host_os in
415                 mingw*)
416                         case $host_cpu in
417                                 i?86)   enable_threads=win95 ;;
418                                 *)      enable_threads=vista ;;
419                         esac
420                         ;;
421                 *)
422                         enable_threads=posix
423                         ;;
424         esac
427 case $enable_threads in
428         posix | win95 | vista)
429                 AC_MSG_RESULT([yes, $enable_threads])
430                 ;;
431         no)
432                 AC_MSG_RESULT([no])
433                 ;;
434         *)
435                 AC_MSG_RESULT([])
436                 AC_MSG_ERROR([--enable-threads only accepts `yes', `no', `posix', `win95', or `vista'])
437                 ;;
438 esac
440 # The Win95 threading lacks thread-safe one-time initialization function.
441 # It's better to disallow it instead of allowing threaded but thread-unsafe
442 # build.
443 if test "x$enable_small$enable_threads" = xyeswin95; then
444         AC_MSG_ERROR([--enable-threads=win95 and --enable-small cannot be
445                 used at the same time])
448 # We use the actual result a little later.
451 #########################
452 # Assumed amount of RAM #
453 #########################
455 # We use 128 MiB as default, because it will allow decompressing files
456 # created with "xz -9". It would be slightly safer to guess a lower value,
457 # but most systems, on which we don't have any way to determine the amount
458 # of RAM, will probably have at least 128 MiB of RAM.
459 AC_MSG_CHECKING([how much RAM to assume if the real amount is unknown])
460 AC_ARG_ENABLE([assume-ram], AS_HELP_STRING([--enable-assume-ram=SIZE],
461                 [If and only if the real amount of RAM cannot be determined,
462                 assume SIZE MiB. The default is 128 MiB. This affects the
463                 default memory usage limit.]),
464         [], [enable_assume_ram=128])
465 assume_ram_check=`echo "$enable_assume_ram" | tr -d 0123456789`
466 if test -z "$enable_assume_ram" || test -n "$assume_ram_check"; then
467         AC_MSG_RESULT([])
468         AC_MSG_ERROR([--enable-assume-ram accepts only an integer argument])
470 AC_MSG_RESULT([$enable_assume_ram MiB])
471 AC_DEFINE_UNQUOTED([ASSUME_RAM], [$enable_assume_ram],
472                 [How many MiB of RAM to assume if the real amount cannot
473                 be determined.])
476 #########################
477 # Components to install #
478 #########################
480 AC_ARG_ENABLE([xz], [AS_HELP_STRING([--disable-xz],
481                 [do not build the xz tool])],
482         [], [enable_xz=yes])
483 AM_CONDITIONAL([COND_XZ], [test x$enable_xz != xno])
485 AC_ARG_ENABLE([xzdec], [AS_HELP_STRING([--disable-xzdec],
486                 [do not build xzdec])],
487         [], [enable_xzdec=yes])
488 test "x$enable_decoders" = xno && enable_xzdec=no
489 AM_CONDITIONAL([COND_XZDEC], [test x$enable_xzdec != xno])
491 AC_ARG_ENABLE([lzmadec], [AS_HELP_STRING([--disable-lzmadec],
492                 [do not build lzmadec
493                 (it exists primarily for LZMA Utils compatibility)])],
494         [], [enable_lzmadec=yes])
495 test "x$enable_decoder_lzma1" = xno && enable_lzmadec=no
496 AM_CONDITIONAL([COND_LZMADEC], [test x$enable_lzmadec != xno])
498 AC_ARG_ENABLE([lzmainfo], [AS_HELP_STRING([--disable-lzmainfo],
499                 [do not build lzmainfo
500                 (it exists primarily for LZMA Utils compatibility)])],
501         [], [enable_lzmainfo=yes])
502 test "x$enable_decoder_lzma1" = xno && enable_lzmainfo=no
503 AM_CONDITIONAL([COND_LZMAINFO], [test x$enable_lzmainfo != xno])
505 AC_ARG_ENABLE([lzma-links], [AS_HELP_STRING([--disable-lzma-links],
506                 [do not create symlinks for LZMA Utils compatibility])],
507         [], [enable_lzma_links=yes])
508 AM_CONDITIONAL([COND_LZMALINKS], [test x$enable_lzma_links != xno])
510 AC_ARG_ENABLE([scripts], [AS_HELP_STRING([--disable-scripts],
511                 [do not install the scripts xzdiff, xzgrep, xzless, xzmore,
512                 and their symlinks])],
513         [], [enable_scripts=yes])
514 AM_CONDITIONAL([COND_SCRIPTS], [test x$enable_scripts != xno])
516 AC_ARG_ENABLE([doc], [AS_HELP_STRING([--disable-doc],
517                 [do not install documentation files to docdir
518                 (man pages will still be installed)])],
519         [], [enable_doc=yes])
520 AM_CONDITIONAL([COND_DOC], [test x$enable_doc != xno])
523 ##############
524 # Sandboxing #
525 ##############
527 AC_MSG_CHECKING([if sandboxing should be used])
528 AC_ARG_ENABLE([sandbox], [AS_HELP_STRING([--enable-sandbox=METHOD],
529                 [Sandboxing METHOD can be
530                 `auto', `no', `capsicum', or `pledge'.
531                 The default is `auto' which enables sandboxing if
532                 a supported sandboxing method is found.])],
533         [], [enable_sandbox=auto])
534 case $enable_sandbox in
535         auto)
536                 AC_MSG_RESULT([maybe (autodetect)])
537                 ;;
538         no | capsicum | pledge)
539                 AC_MSG_RESULT([$enable_sandbox])
540                 ;;
541         *)
542                 AC_MSG_RESULT([])
543                 AC_MSG_ERROR([--enable-sandbox only accepts `auto', `no', `capsicum', or `pledge'.])
544                 ;;
545 esac
548 ###########################
549 # PATH prefix for scripts #
550 ###########################
552 # The scripts can add a prefix to the search PATH so that POSIX tools
553 # or the xz binary is always in the PATH.
554 AC_ARG_ENABLE([path-for-scripts],
555         [AS_HELP_STRING([--enable-path-for-scripts=PREFIX],
556                 [If PREFIX isn't empty, PATH=PREFIX:$PATH will be set in
557                 the beginning of the scripts (xzgrep and others).
558                 The default is empty except on Solaris the default is
559                 /usr/xpg4/bin.])],
560         [], [
561                 case $host_os in
562                         solaris*) enable_path_for_scripts=/usr/xpg4/bin ;;
563                         *)        enable_path_for_scripts= ;;
564                 esac
565         ])
566 if test -n "$enable_path_for_scripts" && test "x$enable_path_for_scripts" != xno ; then
567         enable_path_for_scripts="PATH=$enable_path_for_scripts:\$PATH"
568 else
569         enable_path_for_scripts=
571 AC_SUBST([enable_path_for_scripts])
574 ###############################################################################
575 # Checks for programs.
576 ###############################################################################
578 echo
579 case $host_os in
580         solaris*)
581                 # The gnulib POSIX shell macro below may pick a shell that
582                 # doesn't work with xzgrep. Workaround by picking a shell
583                 # that is known to work.
584                 if test -z "$gl_cv_posix_shell" && test -x /usr/xpg4/bin/sh; then
585                         gl_cv_posix_shell=/usr/xpg4/bin/sh
586                 fi
587                 ;;
588 esac
589 gl_POSIX_SHELL
590 if test -z "$POSIX_SHELL" && test "x$enable_scripts" = xyes ; then
591         AC_MSG_ERROR([No POSIX conforming shell (sh) was found.])
594 echo
595 echo "Initializing Automake:"
597 # We don't use "subdir-objects" yet because it breaks "make distclean" when
598 # dependencies are enabled (as of Automake 1.14.1) due to this bug:
599 # https://debbugs.gnu.org/cgi/bugreport.cgi?bug=17354
600 # The -Wno-unsupported is used to silence warnings about missing
601 # "subdir-objects".
602 AM_INIT_AUTOMAKE([1.12 foreign tar-v7 filename-length-max=99 -Wno-unsupported])
603 AC_PROG_LN_S
605 dnl # Autoconf >= 2.70 warns that AC_PROG_CC_C99 is obsolete. However,
606 dnl # we have to keep using AC_PROG_CC_C99 instead of AC_PROG_CC
607 dnl # as long as we try to be compatible with Autoconf 2.69.
608 AC_PROG_CC_C99
609 if test x$ac_cv_prog_cc_c99 = xno ; then
610         AC_MSG_ERROR([No C99 compiler was found.])
613 AM_PROG_CC_C_O
614 AM_PROG_AS
615 AC_USE_SYSTEM_EXTENSIONS
617 AS_CASE([$enable_threads],
618         [posix], [
619                 echo
620                 echo "POSIX threading support:"
621                 AX_PTHREAD([:]) dnl We don't need the HAVE_PTHREAD macro.
622                 LIBS="$LIBS $PTHREAD_LIBS"
623                 AM_CFLAGS="$AM_CFLAGS $PTHREAD_CFLAGS"
625                 dnl NOTE: PTHREAD_CC is ignored. It would be useful on AIX,
626                 dnl but it's tricky to get it right together with
627                 dnl AC_PROG_CC_C99. Thus, this is handled by telling the
628                 dnl user in INSTALL to set the correct CC manually.
630                 AC_DEFINE([MYTHREAD_POSIX], [1],
631                         [Define to 1 when using POSIX threads (pthreads).])
633                 # These are nice to have but not mandatory.
634                 #
635                 # FIXME: xz uses clock_gettime if it is available and can do
636                 # it even when threading is disabled. Moving this outside
637                 # of pthread detection may be undesirable because then
638                 # liblzma may get linked against librt even when librt isn't
639                 # needed by liblzma.
640                 OLD_CFLAGS=$CFLAGS
641                 CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
642                 AC_SEARCH_LIBS([clock_gettime], [rt])
643                 AC_CHECK_FUNCS([clock_gettime pthread_condattr_setclock])
644                 AC_CHECK_DECL([CLOCK_MONOTONIC], [AC_DEFINE(
645                         [HAVE_CLOCK_MONOTONIC], [1], [Define to 1 if
646                         `CLOCK_MONOTONIC' is declared in <time.h>.])], [],
647                         [[#include <time.h>]])
648                 CFLAGS=$OLD_CFLAGS
649         ],
650         [win95], [
651                 AC_DEFINE([MYTHREAD_WIN95], [1], [Define to 1 when using
652                         Windows 95 (and thus XP) compatible threads.
653                         This avoids use of features that were added in
654                         Windows Vista.])
655         ],
656         [vista], [
657                 AC_DEFINE([MYTHREAD_VISTA], [1], [Define to 1 when using
658                         Windows Vista compatible threads. This uses
659                         features that are not available on Windows XP.])
660         ]
662 AM_CONDITIONAL([COND_THREADS], [test "x$enable_threads" != xno])
664 echo
665 echo "Initializing Libtool:"
666 LT_PREREQ([2.4])
667 LT_INIT([win32-dll])
668 LT_LANG([Windows Resource])
670 # This is a bit wrong since it is possible to request that only some libs
671 # are built as shared. Using that feature isn't so common though, and this
672 # breaks only on Windows (at least for now) if the user enables only some
673 # libs as shared.
674 AM_CONDITIONAL([COND_SHARED], [test "x$enable_shared" != xno])
676 #####################
677 # Symbol versioning #
678 #####################
680 # NOTE: This checks if we are building shared or static library
681 # and if --with-pic or --without-pic was used. Thus this check
682 # must be after Libtool initialization.
683 AC_MSG_CHECKING([if library symbol versioning should be used])
684 AC_ARG_ENABLE([symbol-versions], [AS_HELP_STRING([--enable-symbol-versions],
685                 [Use symbol versioning for liblzma. Enabled by default on
686                 GNU/Linux, other GNU-based systems, and FreeBSD.])],
687         [], [enable_symbol_versions=auto])
688 if test "x$enable_symbol_versions" = xauto; then
689         case $host_os in
690                 # NOTE: Even if one omits -gnu on GNU/Linux (e.g.
691                 # i486-slackware-linux), configure will (via config.sub)
692                 # append -gnu (e.g. i486-slackware-linux-gnu), and this
693                 # test will work correctly.
694                 gnu* | *-gnu* | freebsd*)
695                         enable_symbol_versions=yes
696                         ;;
697                 *)
698                         enable_symbol_versions=no
699                         ;;
700         esac
703 # There are two variants for symbol versioning.
704 # See src/liblzma/validate_map.sh for details.
706 # On GNU/Linux, extra symbols are added in the C code. These extra symbols
707 # must not be put into a static library as they can cause problems (and
708 # even if they didn't cause problems, they would be useless). On other
709 # systems symbol versioning may be used too but there is no problem as only
710 # a linker script is specified in src/liblzma/Makefile.am and that isn't
711 # used when creating a static library.
713 # Libtool always uses -DPIC when building shared libraries by default and
714 # doesn't use it for static libs by default. This can be overriden with
715 # --with-pic and --without-pic though. As long as neither --with-pic nor
716 # --without-pic is used then we can use #ifdef PIC to detect if the file is
717 # being built for a shared library.
718 if test "x$enable_symbol_versions" = xno ; then
719         enable_symbol_versions=no
720         AC_MSG_RESULT([no])
721 elif test "x$enable_shared" = xno ; then
722         enable_symbol_versions=no
723         AC_MSG_RESULT([no (not building a shared library)])
724 else
725         case "$host_cpu-$host_os" in
726                 microblaze*)
727                         # GCC 12 on MicroBlaze doesn't support __symver__
728                         # attribute. It's simplest and safest to use the
729                         # generic version on that platform since then only
730                         # the linker script is needed. The RHEL/CentOS 7
731                         # compatibility symbols don't matter on MicroBlaze.
732                         enable_symbol_versions=generic
733                         ;;
734                 *-linux*)
735                         case "$pic_mode-$enable_static" in
736                                 default-*)
737                                         # Use symvers if PIC is defined.
738                                         have_symbol_versions_linux=2
739                                         ;;
740                                 *-no)
741                                         # Not building static library.
742                                         # Use symvers unconditionally.
743                                         have_symbol_versions_linux=1
744                                         ;;
745                                 *)
746                                         AC_MSG_RESULT([])
747                                         AC_MSG_ERROR([
748     On GNU/Linux, building both shared and static library at the same time
749     is not supported if --with-pic or --without-pic is used.
750     Use either --disable-shared or --disable-static to build one type
751     of library at a time. If both types are needed, build one at a time,
752     possibly picking only src/liblzma/.libs/liblzma.a from the static build.])
753                                         ;;
754                         esac
755                         enable_symbol_versions=linux
756                         AC_DEFINE_UNQUOTED([HAVE_SYMBOL_VERSIONS_LINUX],
757                                 [$have_symbol_versions_linux],
758                                 [Define to 1 to if GNU/Linux-specific details
759                                 are unconditionally wanted for symbol
760                                 versioning. Define to 2 to if these are wanted
761                                 only if also PIC is defined (allows building
762                                 both shared and static liblzma at the same
763                                 time with Libtool if neither --with-pic nor
764                                 --without-pic is used). This define must be
765                                 used together with liblzma_linux.map.])
766                         ;;
767                 *)
768                         enable_symbol_versions=generic
769                         ;;
770         esac
771         AC_MSG_RESULT([yes ($enable_symbol_versions)])
774 AM_CONDITIONAL([COND_SYMVERS_LINUX],
775         [test "x$enable_symbol_versions" = xlinux])
776 AM_CONDITIONAL([COND_SYMVERS_GENERIC],
777         [test "x$enable_symbol_versions" = xgeneric])
780 ###############################################################################
781 # Checks for libraries.
782 ###############################################################################
784 dnl Support for _REQUIRE_VERSION was added in gettext 0.19.6. If both
785 dnl _REQUIRE_VERSION and _VERSION are present, the _VERSION is ignored.
786 dnl We use both for compatibility with other programs in the Autotools family.
787 echo
788 echo "Initializing gettext:"
789 AM_GNU_GETTEXT_REQUIRE_VERSION([0.19.6])
790 AM_GNU_GETTEXT_VERSION([0.19.6])
791 AM_GNU_GETTEXT([external])
794 ###############################################################################
795 # Checks for header files.
796 ###############################################################################
798 echo
799 echo "System headers and functions:"
801 # There is currently no workarounds in this package if some of
802 # these headers are missing.
803 AC_CHECK_HEADERS([fcntl.h limits.h sys/time.h],
804         [],
805         [AC_MSG_ERROR([Required header file(s) are missing.])])
807 # immintrin.h allows the use of the intrinsic functions if they are available.
808 # cpuid.h may be used for detecting x86 processor features at runtime.
809 AC_CHECK_HEADERS([immintrin.h cpuid.h])
812 ###############################################################################
813 # Checks for typedefs, structures, and compiler characteristics.
814 ###############################################################################
816 AC_HEADER_STDBOOL
818 AC_TYPE_UINT8_T
819 AC_TYPE_UINT16_T
820 AC_TYPE_INT32_T
821 AC_TYPE_UINT32_T
822 AC_TYPE_INT64_T
823 AC_TYPE_UINT64_T
824 AC_TYPE_UINTPTR_T
826 AC_CHECK_SIZEOF([size_t])
828 # The command line tool can copy high resolution timestamps if such
829 # information is available in struct stat. Otherwise one second accuracy
830 # is used.
831 AC_CHECK_MEMBERS([
832         struct stat.st_atim.tv_nsec,
833         struct stat.st_atimespec.tv_nsec,
834         struct stat.st_atimensec,
835         struct stat.st_uatime,
836         struct stat.st_atim.st__tim.tv_nsec])
838 AC_SYS_LARGEFILE
839 AC_C_BIGENDIAN
841 # __attribute__((__constructor__)) can be used for one-time initializations.
842 # Use -Werror because some compilers accept unknown attributes and just
843 # give a warning. If it works this should give no warnings, even
844 # clang -Weverything should be fine.
845 # dnl This doesn't need AC_LANG_SOURCE, minimal code is enough.
846 AC_MSG_CHECKING([if __attribute__((__constructor__)) can be used])
847 have_func_attribute_constructor=no
848 OLD_CFLAGS="$CFLAGS"
849 CFLAGS="$CFLAGS -Werror"
850 AC_COMPILE_IFELSE([
851         __attribute__((__constructor__))
852         static void my_constructor_func(void) { return; }
853 ], [
854         AC_DEFINE([HAVE_FUNC_ATTRIBUTE_CONSTRUCTOR], [1],
855                 [Define to 1 if __attribute__((__constructor__))
856                 is supported for functions.])
857         have_func_attribute_constructor=yes
858         AC_MSG_RESULT([yes])
859 ], [
860         AC_MSG_RESULT([no])
862 CFLAGS="$OLD_CFLAGS"
865 ###############################################################################
866 # Checks for library functions.
867 ###############################################################################
869 # Gnulib replacements as needed
870 gl_GETOPT
872 # Find the best function to set timestamps.
873 AC_CHECK_FUNCS([futimens futimes futimesat utimes _futime utime], [break])
875 # This is nice to have but not mandatory.
876 AC_CHECK_FUNCS([posix_fadvise])
878 TUKLIB_PROGNAME
879 TUKLIB_INTEGER
880 TUKLIB_PHYSMEM
881 TUKLIB_CPUCORES
882 TUKLIB_MBSTR
884 # If requested, check for system-provided SHA-256. At least the following
885 # implementations are supported:
887 # OS       Headers                     Library  Type           Function
888 # FreeBSD  sys/types.h + sha256.h      libmd    SHA256_CTX     SHA256_Init
889 # NetBSD   sys/types.h + sha2.h                 SHA256_CTX     SHA256_Init
890 # OpenBSD  sys/types.h + sha2.h                 SHA2_CTX       SHA256Init
891 # Solaris  sys/types.h + sha2.h        libmd    SHA256_CTX     SHA256Init
892 # MINIX 3  sys/types.h + sha2.h                 SHA256_CTX     SHA256_Init
893 # Darwin   CommonCrypto/CommonDigest.h          CC_SHA256_CTX  CC_SHA256_Init
895 # Note that Darwin's CC_SHA256_Update takes buffer size as uint32_t instead
896 # of size_t.
898 sha256_header_found=no
899 sha256_type_found=no
900 sha256_func_found=no
901 AS_IF([test "x$enable_external_sha256" = "xyes"], [
902         # Test for Common Crypto before others, because Darwin has sha256.h
903         # too and we don't want to use that, because on older versions it
904         # uses OpenSSL functions, whose SHA256_Init is not guaranteed to
905         # succeed.
906         AC_CHECK_HEADERS(
907                 [CommonCrypto/CommonDigest.h sha256.h sha2.h],
908                 [sha256_header_found=yes ; break])
909         if test "x$sha256_header_found" = xyes; then
910                 AC_CHECK_TYPES([CC_SHA256_CTX, SHA256_CTX, SHA2_CTX],
911                         [sha256_type_found=yes], [],
912                         [[#ifdef HAVE_SYS_TYPES_H
913                           # include <sys/types.h>
914                           #endif
915                           #ifdef HAVE_COMMONCRYPTO_COMMONDIGEST_H
916                           # include <CommonCrypto/CommonDigest.h>
917                           #endif
918                           #ifdef HAVE_SHA256_H
919                           # include <sha256.h>
920                           #endif
921                           #ifdef HAVE_SHA2_H
922                           # include <sha2.h>
923                           #endif]])
924                 if test "x$sha256_type_found" = xyes ; then
925                         AC_SEARCH_LIBS([SHA256Init], [md])
926                         AC_SEARCH_LIBS([SHA256_Init], [md])
927                         AC_CHECK_FUNCS([CC_SHA256_Init SHA256Init SHA256_Init],
928                                 [sha256_func_found=yes ; break])
929                 fi
930         fi
932 AM_CONDITIONAL([COND_INTERNAL_SHA256], [test "x$sha256_func_found" = xno])
933 if test "x$enable_external_sha256$sha256_func_found" = xyesno; then
934         AC_MSG_ERROR([--enable-external-sha256 was specified but no supported external SHA-256 implementation was found])
937 # Check for SSE2 intrinsics. There is no run-time detection for SSE2 so if
938 # compiler options enable SSE2 then SSE2 support is required by the binaries.
939 # The compile-time check for SSE2 is done with #ifdefs because some compilers
940 # (ICC, MSVC) allow SSE2 intrinsics even when SSE2 isn't enabled.
941 AC_CHECK_DECL([_mm_movemask_epi8],
942         [AC_DEFINE([HAVE__MM_MOVEMASK_EPI8], [1],
943                 [Define to 1 if _mm_movemask_epi8 is available.])],
944         [],
945 [#ifdef HAVE_IMMINTRIN_H
946 #include <immintrin.h>
947 #endif])
949 # For faster CRC on 32/64-bit x86 and E2K (see also crc64_fast.c):
951 #   - Check for the CLMUL intrinsic _mm_clmulepi64_si128 in <immintrin.h>.
952 #     Check also for _mm_set_epi64x for consistency with CMake build
953 #     where it's needed to disable CLMUL with VS2013.
955 #   - Check that __attribute__((__target__("ssse3,sse4.1,pclmul"))) works
956 #     together with _mm_clmulepi64_si128 from <immintrin.h>. The attribute
957 #     was added in GCC 4.4 but some GCC 4.x versions don't allow intrinsics
958 #     with it. Exception: it must be not be used with EDG-based compilers
959 #     like ICC and the compiler on E2K.
961 # If everything above is supported, runtime detection will be used to keep the
962 # binaries working on systems that don't support the required extensions.
963 AC_MSG_CHECKING([if _mm_clmulepi64_si128 is usable])
964 AS_IF([test "x$enable_clmul_crc" = xno], [
965         AC_MSG_RESULT([no, --disable-clmul-crc was used])
966 ], [
967         AC_COMPILE_IFELSE([AC_LANG_SOURCE([[
968 #include <immintrin.h>
970 // CLMUL works on older E2K instruction set but it is slow due to emulation.
971 #if defined(__e2k__) && __iset__ < 6
972 #       error
973 #endif
975 // Intel's old compiler (ICC) can define __GNUC__ but the attribute must not
976 // be used with it. The new Clang-based ICX needs the attribute.
977 // Checking for !defined(__EDG__) catches ICC and other EDG-based compilers.
978 #if (defined(__GNUC__) || defined(__clang__)) && !defined(__EDG__)
979 __attribute__((__target__("ssse3,sse4.1,pclmul")))
980 #endif
981 __m128i my_clmul(__m128i a)
983         const __m128i b = _mm_set_epi64x(1, 2);
984         return _mm_clmulepi64_si128(a, b, 0);
986         ]])], [
987                 AC_DEFINE([HAVE_USABLE_CLMUL], [1],
988                         [Define to 1 if _mm_set_epi64x and
989                         _mm_clmulepi64_si128 are usable.
990                         See configure.ac for details.])
991                 AC_MSG_RESULT([yes])
992         ], [
993                 AC_MSG_RESULT([no])
994         ])
997 # Check for sandbox support. If one is found, set enable_sandbox=found.
998 AS_CASE([$enable_sandbox],
999         [auto | capsicum], [
1000                 AX_CHECK_CAPSICUM([enable_sandbox=found], [:])
1001         ]
1003 AS_CASE([$enable_sandbox],
1004         [auto | pledge], [
1005                 AC_CHECK_FUNCS([pledge], [enable_sandbox=found ; break])
1006         ]
1009 # If a specific sandboxing method was explicitly requested and it wasn't
1010 # found, give an error.
1011 case $enable_sandbox in
1012         auto | no | found)
1013                 ;;
1014         *)
1015                 AC_MSG_ERROR([$enable_sandbox support not found])
1016                 ;;
1017 esac
1020 ###############################################################################
1021 # If using GCC, set some additional AM_CFLAGS:
1022 ###############################################################################
1024 if test "$GCC" = yes ; then
1025         echo
1026         echo "GCC extensions:"
1029 # Always do the visibility check but don't set AM_CFLAGS on Windows.
1030 # This way things get set properly even on Windows.
1031 gl_VISIBILITY
1032 if test -n "$CFLAG_VISIBILITY" && test "$is_w32" = no; then
1033         AM_CFLAGS="$AM_CFLAGS $CFLAG_VISIBILITY"
1036 AS_IF([test "$GCC" = yes], [
1037         # Enable as much warnings as possible. These commented warnings won't
1038         # work for this package though:
1039         #   * -Wunreachable-code breaks several assert(0) cases, which are
1040         #     backed up with "return LZMA_PROG_ERROR".
1041         #   * -Wcast-qual would break various things where we need a non-const
1042         #     pointer although we don't modify anything through it.
1043         #   * -Winline, -Wdisabled-optimization, -Wunsafe-loop-optimizations
1044         #     don't seem so useful here; at least the last one gives some
1045         #     warnings which are not bugs.
1046         #   * -Wconversion still shows too many warnings.
1047         #
1048         # The flags before the empty line are for GCC and many of them
1049         # are supported by Clang too. The flags after the empty line are
1050         # for Clang.
1051         for NEW_FLAG in \
1052                         -Wall \
1053                         -Wextra \
1054                         -Wvla \
1055                         -Wc99-c11-compat \
1056                         -Wformat=2 \
1057                         -Winit-self \
1058                         -Wmissing-include-dirs \
1059                         -Wshift-overflow=2 \
1060                         -Wstrict-overflow=3 \
1061                         -Walloc-zero \
1062                         -Wduplicated-cond \
1063                         -Wfloat-equal \
1064                         -Wundef \
1065                         -Wshadow \
1066                         -Wpointer-arith \
1067                         -Wbad-function-cast \
1068                         -Wwrite-strings \
1069                         -Wdate-time \
1070                         -Wsign-conversion \
1071                         -Wfloat-conversion \
1072                         -Wlogical-op \
1073                         -Waggregate-return \
1074                         -Wstrict-prototypes \
1075                         -Wold-style-definition \
1076                         -Wmissing-prototypes \
1077                         -Wmissing-declarations \
1078                         -Wredundant-decls \
1079                         \
1080                         -Wc99-compat \
1081                         -Wc11-extensions \
1082                         -Wc2x-compat \
1083                         -Wc2x-extensions \
1084                         -Wpre-c2x-compat \
1085                         -Warray-bounds-pointer-arithmetic \
1086                         -Wassign-enum \
1087                         -Wconditional-uninitialized \
1088                         -Wdocumentation \
1089                         -Wduplicate-enum \
1090                         -Wempty-translation-unit \
1091                         -Wflexible-array-extensions \
1092                         -Wmissing-variable-declarations \
1093                         -Wnewline-eof \
1094                         -Wshift-sign-overflow \
1095                         -Wstring-conversion
1096         do
1097                 AC_MSG_CHECKING([if $CC accepts $NEW_FLAG])
1098                 OLD_CFLAGS="$CFLAGS"
1099                 CFLAGS="$CFLAGS $NEW_FLAG -Werror"
1100                 AC_COMPILE_IFELSE([AC_LANG_SOURCE(
1101                                 [void foo(void); void foo(void) { }])], [
1102                         AM_CFLAGS="$AM_CFLAGS $NEW_FLAG"
1103                         AC_MSG_RESULT([yes])
1104                 ], [
1105                         AC_MSG_RESULT([no])
1106                 ])
1107                 CFLAGS="$OLD_CFLAGS"
1108         done
1110         AC_ARG_ENABLE([werror],
1111                 AS_HELP_STRING([--enable-werror], [Enable -Werror to abort
1112                         compilation on all compiler warnings.]),
1113                 [], [enable_werror=no])
1114         if test "x$enable_werror" = "xyes"; then
1115                 AM_CFLAGS="$AM_CFLAGS -Werror"
1116         fi
1120 ###############################################################################
1121 # Create the makefiles and config.h
1122 ###############################################################################
1124 echo
1126 # Don't build the lib directory at all if we don't need any replacement
1127 # functions.
1128 AM_CONDITIONAL([COND_GNULIB], test -n "$LIBOBJS")
1130 # Add default AM_CFLAGS.
1131 AC_SUBST([AM_CFLAGS])
1133 # This is needed for src/scripts.
1134 xz=`echo xz | sed "$program_transform_name"`
1135 AC_SUBST([xz])
1137 AC_CONFIG_FILES([
1138         Makefile
1139         po/Makefile.in
1140         lib/Makefile
1141         src/Makefile
1142         src/liblzma/Makefile
1143         src/liblzma/api/Makefile
1144         src/xz/Makefile
1145         src/xzdec/Makefile
1146         src/lzmainfo/Makefile
1147         src/scripts/Makefile
1148         tests/Makefile
1149         debug/Makefile
1151 AC_CONFIG_FILES([src/scripts/xzdiff], [chmod +x src/scripts/xzdiff])
1152 AC_CONFIG_FILES([src/scripts/xzgrep], [chmod +x src/scripts/xzgrep])
1153 AC_CONFIG_FILES([src/scripts/xzmore], [chmod +x src/scripts/xzmore])
1154 AC_CONFIG_FILES([src/scripts/xzless], [chmod +x src/scripts/xzless])
1156 AC_OUTPUT
1158 # Some warnings
1159 if test x$tuklib_cv_physmem_method = xunknown; then
1160         echo
1161         echo "WARNING:"
1162         echo "No supported method to detect the amount of RAM."
1163         echo "Consider using --enable-assume-ram (if you didn't already)"
1164         echo "or make a patch to add support for this operating system."
1167 if test x$tuklib_cv_cpucores_method = xunknown; then
1168         echo
1169         echo "WARNING:"
1170         echo "No supported method to detect the number of CPU cores."
1173 if test "x$enable_threads$enable_small$have_func_attribute_constructor" \
1174                 = xnoyesno; then
1175         echo
1176         echo "NOTE:"
1177         echo "liblzma will be thread-unsafe due to the combination"
1178         echo "of --disable-threads --enable-small when using a compiler"
1179         echo "that doesn't support __attribute__((__constructor__))."