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      1 # SPDX-License-Identifier: GPL-3.0-or-later WITH Autoconf-exception-3.0
      2 #
      3 # ===========================================================================
      4 #        https://www.gnu.org/software/autoconf-archive/ax_pthread.html
      5 # ===========================================================================
      6 #
      7 # SYNOPSIS
      8 #
      9 #   AX_PTHREAD([ACTION-IF-FOUND[, ACTION-IF-NOT-FOUND]])
     10 #
     11 # DESCRIPTION
     12 #
     13 #   This macro figures out how to build C programs using POSIX threads. It
     14 #   sets the PTHREAD_LIBS output variable to the threads library and linker
     15 #   flags, and the PTHREAD_CFLAGS output variable to any special C compiler
     16 #   flags that are needed. (The user can also force certain compiler
     17 #   flags/libs to be tested by setting these environment variables.)
     18 #
     19 #   Also sets PTHREAD_CC and PTHREAD_CXX to any special C compiler that is
     20 #   needed for multi-threaded programs (defaults to the value of CC
     21 #   respectively CXX otherwise). (This is necessary on e.g. AIX to use the
     22 #   special cc_r/CC_r compiler alias.)
     23 #
     24 #   NOTE: You are assumed to not only compile your program with these flags,
     25 #   but also to link with them as well. For example, you might link with
     26 #   $PTHREAD_CC $CFLAGS $PTHREAD_CFLAGS $LDFLAGS ... $PTHREAD_LIBS $LIBS
     27 #   $PTHREAD_CXX $CXXFLAGS $PTHREAD_CFLAGS $LDFLAGS ... $PTHREAD_LIBS $LIBS
     28 #
     29 #   If you are only building threaded programs, you may wish to use these
     30 #   variables in your default LIBS, CFLAGS, and CC:
     31 #
     32 #     LIBS="$PTHREAD_LIBS $LIBS"
     33 #     CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
     34 #     CXXFLAGS="$CXXFLAGS $PTHREAD_CFLAGS"
     35 #     CC="$PTHREAD_CC"
     36 #     CXX="$PTHREAD_CXX"
     37 #
     38 #   In addition, if the PTHREAD_CREATE_JOINABLE thread-attribute constant
     39 #   has a nonstandard name, this macro defines PTHREAD_CREATE_JOINABLE to
     40 #   that name (e.g. PTHREAD_CREATE_UNDETACHED on AIX).
     41 #
     42 #   Also HAVE_PTHREAD_PRIO_INHERIT is defined if pthread is found and the
     43 #   PTHREAD_PRIO_INHERIT symbol is defined when compiling with
     44 #   PTHREAD_CFLAGS.
     45 #
     46 #   ACTION-IF-FOUND is a list of shell commands to run if a threads library
     47 #   is found, and ACTION-IF-NOT-FOUND is a list of commands to run it if it
     48 #   is not found. If ACTION-IF-FOUND is not specified, the default action
     49 #   will define HAVE_PTHREAD.
     50 #
     51 #   Please let the authors know if this macro fails on any platform, or if
     52 #   you have any other suggestions or comments. This macro was based on work
     53 #   by SGJ on autoconf scripts for FFTW (http://www.fftw.org/) (with help
     54 #   from M. Frigo), as well as ac_pthread and hb_pthread macros posted by
     55 #   Alejandro Forero Cuervo to the autoconf macro repository. We are also
     56 #   grateful for the helpful feedback of numerous users.
     57 #
     58 #   Updated for Autoconf 2.68 by Daniel Richard G.
     59 #
     60 # LICENSE
     61 #
     62 #   Copyright (c) 2008 Steven G. Johnson <stevenj (a] alum.mit.edu>
     63 #   Copyright (c) 2011 Daniel Richard G. <skunk (a] iSKUNK.ORG>
     64 #   Copyright (c) 2019 Marc Stevens <marc.stevens (a] cwi.nl>
     65 #
     66 #   This program is free software: you can redistribute it and/or modify it
     67 #   under the terms of the GNU General Public License as published by the
     68 #   Free Software Foundation, either version 3 of the License, or (at your
     69 #   option) any later version.
     70 #
     71 #   This program is distributed in the hope that it will be useful, but
     72 #   WITHOUT ANY WARRANTY; without even the implied warranty of
     73 #   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
     74 #   Public License for more details.
     75 #
     76 #   You should have received a copy of the GNU General Public License along
     77 #   with this program. If not, see <https://www.gnu.org/licenses/>.
     78 #
     79 #   As a special exception, the respective Autoconf Macro's copyright owner
     80 #   gives unlimited permission to copy, distribute and modify the configure
     81 #   scripts that are the output of Autoconf when processing the Macro. You
     82 #   need not follow the terms of the GNU General Public License when using
     83 #   or distributing such scripts, even though portions of the text of the
     84 #   Macro appear in them. The GNU General Public License (GPL) does govern
     85 #   all other use of the material that constitutes the Autoconf Macro.
     86 #
     87 #   This special exception to the GPL applies to versions of the Autoconf
     88 #   Macro released by the Autoconf Archive. When you make and distribute a
     89 #   modified version of the Autoconf Macro, you may extend this special
     90 #   exception to the GPL to apply to your modified version as well.
     91 
     92 #serial 30
     93 
     94 AU_ALIAS([ACX_PTHREAD], [AX_PTHREAD])
     95 AC_DEFUN([AX_PTHREAD], [
     96 AC_REQUIRE([AC_CANONICAL_TARGET])
     97 AC_REQUIRE([AC_PROG_CC])
     98 AC_REQUIRE([AC_PROG_SED])
     99 AC_LANG_PUSH([C])
    100 ax_pthread_ok=no
    101 
    102 # We used to check for pthread.h first, but this fails if pthread.h
    103 # requires special compiler flags (e.g. on Tru64 or Sequent).
    104 # It gets checked for in the link test anyway.
    105 
    106 # First of all, check if the user has set any of the PTHREAD_LIBS,
    107 # etcetera environment variables, and if threads linking works using
    108 # them:
    109 if test "x$PTHREAD_CFLAGS$PTHREAD_LIBS" != "x"; then
    110         ax_pthread_save_CC="$CC"
    111         ax_pthread_save_CFLAGS="$CFLAGS"
    112         ax_pthread_save_LIBS="$LIBS"
    113         AS_IF([test "x$PTHREAD_CC" != "x"], [CC="$PTHREAD_CC"])
    114         AS_IF([test "x$PTHREAD_CXX" != "x"], [CXX="$PTHREAD_CXX"])
    115         CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
    116         LIBS="$PTHREAD_LIBS $LIBS"
    117         AC_MSG_CHECKING([for pthread_join using $CC $PTHREAD_CFLAGS $PTHREAD_LIBS])
    118         AC_LINK_IFELSE([AC_LANG_CALL([], [pthread_join])], [ax_pthread_ok=yes])
    119         AC_MSG_RESULT([$ax_pthread_ok])
    120         if test "x$ax_pthread_ok" = "xno"; then
    121                 PTHREAD_LIBS=""
    122                 PTHREAD_CFLAGS=""
    123         fi
    124         CC="$ax_pthread_save_CC"
    125         CFLAGS="$ax_pthread_save_CFLAGS"
    126         LIBS="$ax_pthread_save_LIBS"
    127 fi
    128 
    129 # We must check for the threads library under a number of different
    130 # names; the ordering is very important because some systems
    131 # (e.g. DEC) have both -lpthread and -lpthreads, where one of the
    132 # libraries is broken (non-POSIX).
    133 
    134 # Create a list of thread flags to try. Items with a "," contain both
    135 # C compiler flags (before ",") and linker flags (after ","). Other items
    136 # starting with a "-" are C compiler flags, and remaining items are
    137 # library names, except for "none" which indicates that we try without
    138 # any flags at all, and "pthread-config" which is a program returning
    139 # the flags for the Pth emulation library.
    140 
    141 ax_pthread_flags="pthreads none -Kthread -pthread -pthreads -mthreads pthread --thread-safe -mt pthread-config"
    142 
    143 # The ordering *is* (sometimes) important.  Some notes on the
    144 # individual items follow:
    145 
    146 # pthreads: AIX (must check this before -lpthread)
    147 # none: in case threads are in libc; should be tried before -Kthread and
    148 #       other compiler flags to prevent continual compiler warnings
    149 # -Kthread: Sequent (threads in libc, but -Kthread needed for pthread.h)
    150 # -pthread: Linux/gcc (kernel threads), BSD/gcc (userland threads), Tru64
    151 #           (Note: HP C rejects this with "bad form for `-t' option")
    152 # -pthreads: Solaris/gcc (Note: HP C also rejects)
    153 # -mt: Sun Workshop C (may only link SunOS threads [-lthread], but it
    154 #      doesn't hurt to check since this sometimes defines pthreads and
    155 #      -D_REENTRANT too), HP C (must be checked before -lpthread, which
    156 #      is present but should not be used directly; and before -mthreads,
    157 #      because the compiler interprets this as "-mt" + "-hreads")
    158 # -mthreads: Mingw32/gcc, Lynx/gcc
    159 # pthread: Linux, etcetera
    160 # --thread-safe: KAI C++
    161 # pthread-config: use pthread-config program (for GNU Pth library)
    162 
    163 case $target_os in
    164 
    165         freebsd*)
    166 
    167         # -kthread: FreeBSD kernel threads (preferred to -pthread since SMP-able)
    168         # lthread: LinuxThreads port on FreeBSD (also preferred to -pthread)
    169 
    170         ax_pthread_flags="-kthread lthread $ax_pthread_flags"
    171         ;;
    172 
    173         hpux*)
    174 
    175         # From the cc(1) man page: "[-mt] Sets various -D flags to enable
    176         # multi-threading and also sets -lpthread."
    177 
    178         ax_pthread_flags="-mt -pthread pthread $ax_pthread_flags"
    179         ;;
    180 
    181         openedition*)
    182 
    183         # IBM z/OS requires a feature-test macro to be defined in order to
    184         # enable POSIX threads at all, so give the user a hint if this is
    185         # not set. (We don't define these ourselves, as they can affect
    186         # other portions of the system API in unpredictable ways.)
    187 
    188         AC_EGREP_CPP([AX_PTHREAD_ZOS_MISSING],
    189             [
    190 #            if !defined(_OPEN_THREADS) && !defined(_UNIX03_THREADS)
    191              AX_PTHREAD_ZOS_MISSING
    192 #            endif
    193             ],
    194             [AC_MSG_WARN([IBM z/OS requires -D_OPEN_THREADS or -D_UNIX03_THREADS to enable pthreads support.])])
    195         ;;
    196 
    197         solaris*)
    198 
    199         # On Solaris (at least, for some versions), libc contains stubbed
    200         # (non-functional) versions of the pthreads routines, so link-based
    201         # tests will erroneously succeed. (N.B.: The stubs are missing
    202         # pthread_cleanup_push, or rather a function called by this macro,
    203         # so we could check for that, but who knows whether they'll stub
    204         # that too in a future libc.)  So we'll check first for the
    205         # standard Solaris way of linking pthreads (-mt -lpthread).
    206 
    207         ax_pthread_flags="-mt,-lpthread pthread $ax_pthread_flags"
    208         ;;
    209 esac
    210 
    211 # Are we compiling with Clang?
    212 
    213 AC_CACHE_CHECK([whether $CC is Clang],
    214     [ax_cv_PTHREAD_CLANG],
    215     [ax_cv_PTHREAD_CLANG=no
    216      # Note that Autoconf sets GCC=yes for Clang as well as GCC
    217      if test "x$GCC" = "xyes"; then
    218         AC_EGREP_CPP([AX_PTHREAD_CC_IS_CLANG],
    219             [/* Note: Clang 2.7 lacks __clang_[a-z]+__ */
    220 #            if defined(__clang__) && defined(__llvm__)
    221              AX_PTHREAD_CC_IS_CLANG
    222 #            endif
    223             ],
    224             [ax_cv_PTHREAD_CLANG=yes])
    225      fi
    226     ])
    227 ax_pthread_clang="$ax_cv_PTHREAD_CLANG"
    228 
    229 
    230 # GCC generally uses -pthread, or -pthreads on some platforms (e.g. SPARC)
    231 
    232 # Note that for GCC and Clang -pthread generally implies -lpthread,
    233 # except when -nostdlib is passed.
    234 # This is problematic using libtool to build C++ shared libraries with pthread:
    235 # [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=25460
    236 # [2] https://bugzilla.redhat.com/show_bug.cgi?id=661333
    237 # [3] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=468555
    238 # To solve this, first try -pthread together with -lpthread for GCC
    239 
    240 AS_IF([test "x$GCC" = "xyes"],
    241       [ax_pthread_flags="-pthread,-lpthread -pthread -pthreads $ax_pthread_flags"])
    242 
    243 # Clang takes -pthread (never supported any other flag), but we'll try with -lpthread first
    244 
    245 AS_IF([test "x$ax_pthread_clang" = "xyes"],
    246       [ax_pthread_flags="-pthread,-lpthread -pthread"])
    247 
    248 
    249 # The presence of a feature test macro requesting re-entrant function
    250 # definitions is, on some systems, a strong hint that pthreads support is
    251 # correctly enabled
    252 
    253 case $target_os in
    254         darwin* | hpux* | linux* | osf* | solaris*)
    255         ax_pthread_check_macro="_REENTRANT"
    256         ;;
    257 
    258         aix*)
    259         ax_pthread_check_macro="_THREAD_SAFE"
    260         ;;
    261 
    262         *)
    263         ax_pthread_check_macro="--"
    264         ;;
    265 esac
    266 AS_IF([test "x$ax_pthread_check_macro" = "x--"],
    267       [ax_pthread_check_cond=0],
    268       [ax_pthread_check_cond="!defined($ax_pthread_check_macro)"])
    269 
    270 
    271 if test "x$ax_pthread_ok" = "xno"; then
    272 for ax_pthread_try_flag in $ax_pthread_flags; do
    273 
    274         case $ax_pthread_try_flag in
    275                 none)
    276                 AC_MSG_CHECKING([whether pthreads work without any flags])
    277                 ;;
    278 
    279                 *,*)
    280                 PTHREAD_CFLAGS=`echo $ax_pthread_try_flag | sed "s/^\(.*\),\(.*\)$/\1/"`
    281                 PTHREAD_LIBS=`echo $ax_pthread_try_flag | sed "s/^\(.*\),\(.*\)$/\2/"`
    282                 AC_MSG_CHECKING([whether pthreads work with "$PTHREAD_CFLAGS" and "$PTHREAD_LIBS"])
    283                 ;;
    284 
    285                 -*)
    286                 AC_MSG_CHECKING([whether pthreads work with $ax_pthread_try_flag])
    287                 PTHREAD_CFLAGS="$ax_pthread_try_flag"
    288                 ;;
    289 
    290                 pthread-config)
    291                 AC_CHECK_PROG([ax_pthread_config], [pthread-config], [yes], [no])
    292                 AS_IF([test "x$ax_pthread_config" = "xno"], [continue])
    293                 PTHREAD_CFLAGS="`pthread-config --cflags`"
    294                 PTHREAD_LIBS="`pthread-config --ldflags` `pthread-config --libs`"
    295                 ;;
    296 
    297                 *)
    298                 AC_MSG_CHECKING([for the pthreads library -l$ax_pthread_try_flag])
    299                 PTHREAD_LIBS="-l$ax_pthread_try_flag"
    300                 ;;
    301         esac
    302 
    303         ax_pthread_save_CFLAGS="$CFLAGS"
    304         ax_pthread_save_LIBS="$LIBS"
    305         CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
    306         LIBS="$PTHREAD_LIBS $LIBS"
    307 
    308         # Check for various functions.  We must include pthread.h,
    309         # since some functions may be macros.  (On the Sequent, we
    310         # need a special flag -Kthread to make this header compile.)
    311         # We check for pthread_join because it is in -lpthread on IRIX
    312         # while pthread_create is in libc.  We check for pthread_attr_init
    313         # due to DEC craziness with -lpthreads.  We check for
    314         # pthread_cleanup_push because it is one of the few pthread
    315         # functions on Solaris that doesn't have a non-functional libc stub.
    316         # We try pthread_create on general principles.
    317 
    318         AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <pthread.h>
    319 #                       if $ax_pthread_check_cond
    320 #                        error "$ax_pthread_check_macro must be defined"
    321 #                       endif
    322                         static void *some_global = NULL;
    323                         static void routine(void *a)
    324                           {
    325                              /* To avoid any unused-parameter or
    326                                 unused-but-set-parameter warning.  */
    327                              some_global = a;
    328                           }
    329                         static void *start_routine(void *a) { return a; }],
    330                        [pthread_t th; pthread_attr_t attr;
    331                         pthread_create(&th, 0, start_routine, 0);
    332                         pthread_join(th, 0);
    333                         pthread_attr_init(&attr);
    334                         pthread_cleanup_push(routine, 0);
    335                         pthread_cleanup_pop(0) /* ; */])],
    336             [ax_pthread_ok=yes],
    337             [])
    338 
    339         CFLAGS="$ax_pthread_save_CFLAGS"
    340         LIBS="$ax_pthread_save_LIBS"
    341 
    342         AC_MSG_RESULT([$ax_pthread_ok])
    343         AS_IF([test "x$ax_pthread_ok" = "xyes"], [break])
    344 
    345         PTHREAD_LIBS=""
    346         PTHREAD_CFLAGS=""
    347 done
    348 fi
    349 
    350 
    351 # Clang needs special handling, because older versions handle the -pthread
    352 # option in a rather... idiosyncratic way
    353 
    354 if test "x$ax_pthread_clang" = "xyes"; then
    355 
    356         # Clang takes -pthread; it has never supported any other flag
    357 
    358         # (Note 1: This will need to be revisited if a system that Clang
    359         # supports has POSIX threads in a separate library.  This tends not
    360         # to be the way of modern systems, but it's conceivable.)
    361 
    362         # (Note 2: On some systems, notably Darwin, -pthread is not needed
    363         # to get POSIX threads support; the API is always present and
    364         # active.  We could reasonably leave PTHREAD_CFLAGS empty.  But
    365         # -pthread does define _REENTRANT, and while the Darwin headers
    366         # ignore this macro, third-party headers might not.)
    367 
    368         # However, older versions of Clang make a point of warning the user
    369         # that, in an invocation where only linking and no compilation is
    370         # taking place, the -pthread option has no effect ("argument unused
    371         # during compilation").  They expect -pthread to be passed in only
    372         # when source code is being compiled.
    373         #
    374         # Problem is, this is at odds with the way Automake and most other
    375         # C build frameworks function, which is that the same flags used in
    376         # compilation (CFLAGS) are also used in linking.  Many systems
    377         # supported by AX_PTHREAD require exactly this for POSIX threads
    378         # support, and in fact it is often not straightforward to specify a
    379         # flag that is used only in the compilation phase and not in
    380         # linking.  Such a scenario is extremely rare in practice.
    381         #
    382         # Even though use of the -pthread flag in linking would only print
    383         # a warning, this can be a nuisance for well-run software projects
    384         # that build with -Werror.  So if the active version of Clang has
    385         # this misfeature, we search for an option to squash it.
    386 
    387         AC_CACHE_CHECK([whether Clang needs flag to prevent "argument unused" warning when linking with -pthread],
    388             [ax_cv_PTHREAD_CLANG_NO_WARN_FLAG],
    389             [ax_cv_PTHREAD_CLANG_NO_WARN_FLAG=unknown
    390              # Create an alternate version of $ac_link that compiles and
    391              # links in two steps (.c -> .o, .o -> exe) instead of one
    392              # (.c -> exe), because the warning occurs only in the second
    393              # step
    394              ax_pthread_save_ac_link="$ac_link"
    395              ax_pthread_sed='s/conftest\.\$ac_ext/conftest.$ac_objext/g'
    396              ax_pthread_link_step=`AS_ECHO(["$ac_link"]) | sed "$ax_pthread_sed"`
    397              ax_pthread_2step_ac_link="($ac_compile) && (echo ==== >&5) && ($ax_pthread_link_step)"
    398              ax_pthread_save_CFLAGS="$CFLAGS"
    399              for ax_pthread_try in '' -Qunused-arguments -Wno-unused-command-line-argument unknown; do
    400                 AS_IF([test "x$ax_pthread_try" = "xunknown"], [break])
    401                 CFLAGS="-Werror -Wunknown-warning-option $ax_pthread_try -pthread $ax_pthread_save_CFLAGS"
    402                 ac_link="$ax_pthread_save_ac_link"
    403                 AC_LINK_IFELSE([AC_LANG_SOURCE([[int main(void){return 0;}]])],
    404                     [ac_link="$ax_pthread_2step_ac_link"
    405                      AC_LINK_IFELSE([AC_LANG_SOURCE([[int main(void){return 0;}]])],
    406                          [break])
    407                     ])
    408              done
    409              ac_link="$ax_pthread_save_ac_link"
    410              CFLAGS="$ax_pthread_save_CFLAGS"
    411              AS_IF([test "x$ax_pthread_try" = "x"], [ax_pthread_try=no])
    412              ax_cv_PTHREAD_CLANG_NO_WARN_FLAG="$ax_pthread_try"
    413             ])
    414 
    415         case "$ax_cv_PTHREAD_CLANG_NO_WARN_FLAG" in
    416                 no | unknown) ;;
    417                 *) PTHREAD_CFLAGS="$ax_cv_PTHREAD_CLANG_NO_WARN_FLAG $PTHREAD_CFLAGS" ;;
    418         esac
    419 
    420 fi # $ax_pthread_clang = yes
    421 
    422 
    423 
    424 # Various other checks:
    425 if test "x$ax_pthread_ok" = "xyes"; then
    426         ax_pthread_save_CFLAGS="$CFLAGS"
    427         ax_pthread_save_LIBS="$LIBS"
    428         CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
    429         LIBS="$PTHREAD_LIBS $LIBS"
    430 
    431         # Detect AIX lossage: JOINABLE attribute is called UNDETACHED.
    432         AC_CACHE_CHECK([for joinable pthread attribute],
    433             [ax_cv_PTHREAD_JOINABLE_ATTR],
    434             [ax_cv_PTHREAD_JOINABLE_ATTR=unknown
    435              for ax_pthread_attr in PTHREAD_CREATE_JOINABLE PTHREAD_CREATE_UNDETACHED; do
    436                  AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <pthread.h>],
    437                                                  [int attr = $ax_pthread_attr; return attr /* ; */])],
    438                                 [ax_cv_PTHREAD_JOINABLE_ATTR=$ax_pthread_attr; break],
    439                                 [])
    440              done
    441             ])
    442         AS_IF([test "x$ax_cv_PTHREAD_JOINABLE_ATTR" != "xunknown" && \
    443                test "x$ax_cv_PTHREAD_JOINABLE_ATTR" != "xPTHREAD_CREATE_JOINABLE" && \
    444                test "x$ax_pthread_joinable_attr_defined" != "xyes"],
    445               [AC_DEFINE_UNQUOTED([PTHREAD_CREATE_JOINABLE],
    446                                   [$ax_cv_PTHREAD_JOINABLE_ATTR],
    447                                   [Define to necessary symbol if this constant
    448                                    uses a non-standard name on your system.])
    449                ax_pthread_joinable_attr_defined=yes
    450               ])
    451 
    452         AC_CACHE_CHECK([whether more special flags are required for pthreads],
    453             [ax_cv_PTHREAD_SPECIAL_FLAGS],
    454             [ax_cv_PTHREAD_SPECIAL_FLAGS=no
    455              case $target_os in
    456              solaris*)
    457              ax_cv_PTHREAD_SPECIAL_FLAGS="-D_POSIX_PTHREAD_SEMANTICS"
    458              ;;
    459              esac
    460             ])
    461         AS_IF([test "x$ax_cv_PTHREAD_SPECIAL_FLAGS" != "xno" && \
    462                test "x$ax_pthread_special_flags_added" != "xyes"],
    463               [PTHREAD_CFLAGS="$ax_cv_PTHREAD_SPECIAL_FLAGS $PTHREAD_CFLAGS"
    464                ax_pthread_special_flags_added=yes])
    465 
    466         AC_CACHE_CHECK([for PTHREAD_PRIO_INHERIT],
    467             [ax_cv_PTHREAD_PRIO_INHERIT],
    468             [AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <pthread.h>]],
    469                                              [[int i = PTHREAD_PRIO_INHERIT;
    470                                                return i;]])],
    471                             [ax_cv_PTHREAD_PRIO_INHERIT=yes],
    472                             [ax_cv_PTHREAD_PRIO_INHERIT=no])
    473             ])
    474         AS_IF([test "x$ax_cv_PTHREAD_PRIO_INHERIT" = "xyes" && \
    475                test "x$ax_pthread_prio_inherit_defined" != "xyes"],
    476               [AC_DEFINE([HAVE_PTHREAD_PRIO_INHERIT], [1], [Have PTHREAD_PRIO_INHERIT.])
    477                ax_pthread_prio_inherit_defined=yes
    478               ])
    479 
    480         CFLAGS="$ax_pthread_save_CFLAGS"
    481         LIBS="$ax_pthread_save_LIBS"
    482 
    483         # More AIX lossage: compile with *_r variant
    484         if test "x$GCC" != "xyes"; then
    485             case $target_os in
    486                 aix*)
    487                 AS_CASE(["x/$CC"],
    488                     [x*/c89|x*/c89_128|x*/c99|x*/c99_128|x*/cc|x*/cc128|x*/xlc|x*/xlc_v6|x*/xlc128|x*/xlc128_v6],
    489                     [#handle absolute path differently from PATH based program lookup
    490                      AS_CASE(["x$CC"],
    491                          [x/*],
    492                          [
    493 			   AS_IF([AS_EXECUTABLE_P([${CC}_r])],[PTHREAD_CC="${CC}_r"])
    494 			   AS_IF([test "x${CXX}" != "x"], [AS_IF([AS_EXECUTABLE_P([${CXX}_r])],[PTHREAD_CXX="${CXX}_r"])])
    495 			 ],
    496                          [
    497 			   AC_CHECK_PROGS([PTHREAD_CC],[${CC}_r],[$CC])
    498 			   AS_IF([test "x${CXX}" != "x"], [AC_CHECK_PROGS([PTHREAD_CXX],[${CXX}_r],[$CXX])])
    499 			 ]
    500                      )
    501                     ])
    502                 ;;
    503             esac
    504         fi
    505 fi
    506 
    507 test -n "$PTHREAD_CC" || PTHREAD_CC="$CC"
    508 test -n "$PTHREAD_CXX" || PTHREAD_CXX="$CXX"
    509 
    510 AC_SUBST([PTHREAD_LIBS])
    511 AC_SUBST([PTHREAD_CFLAGS])
    512 AC_SUBST([PTHREAD_CC])
    513 AC_SUBST([PTHREAD_CXX])
    514 
    515 # Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND:
    516 if test "x$ax_pthread_ok" = "xyes"; then
    517         ifelse([$1],,[AC_DEFINE([HAVE_PTHREAD],[1],[Define if you have POSIX threads libraries and header files.])],[$1])
    518         :
    519 else
    520         ax_pthread_ok=no
    521         $2
    522 fi
    523 AC_LANG_POP
    524 ])dnl AX_PTHREAD
    525