Update ax_pthread m4 script

1 files changed, 345 insertions, 192 deletions

diff --git a/m4/ax_pthread.m4 b/m4/ax_pthread.m4
index d383ad5..d218d1a 100644
--- a/m4/ax_pthread.m4
+++ b/m4/ax_pthread.m4
@@ -19,10 +19,10 @@
 #   is necessary on AIX to use the special cc_r compiler alias.)
 #
 #   NOTE: You are assumed to not only compile your program with these flags,
-#   but also link it with them as well. e.g. you should link with
+#   but also to link with them as well. For example, you might link with
 #   $PTHREAD_CC $CFLAGS $PTHREAD_CFLAGS $LDFLAGS ... $PTHREAD_LIBS $LIBS
 #
-#   If you are only building threads programs, you may wish to use these
+#   If you are only building threaded programs, you may wish to use these
 #   variables in your default LIBS, CFLAGS, and CC:
 #
 #     LIBS="$PTHREAD_LIBS $LIBS"
@@ -30,8 +30,8 @@
 #     CC="$PTHREAD_CC"
 #
 #   In addition, if the PTHREAD_CREATE_JOINABLE thread-attribute constant
-#   has a nonstandard name, defines PTHREAD_CREATE_JOINABLE to that name
-#   (e.g. PTHREAD_CREATE_UNDETACHED on AIX).
+#   has a nonstandard name, this macro defines PTHREAD_CREATE_JOINABLE to
+#   that name (e.g. PTHREAD_CREATE_UNDETACHED on AIX).
 #
 #   Also HAVE_PTHREAD_PRIO_INHERIT is defined if pthread is found and the
 #   PTHREAD_PRIO_INHERIT symbol is defined when compiling with
@@ -82,35 +82,40 @@
 #   modified version of the Autoconf Macro, you may extend this special
 #   exception to the GPL to apply to your modified version as well.
 
-#serial 21
+#serial 22
 
 AU_ALIAS([ACX_PTHREAD], [AX_PTHREAD])
 AC_DEFUN([AX_PTHREAD], [
 AC_REQUIRE([AC_CANONICAL_HOST])
+AC_REQUIRE([AC_PROG_CC])
+AC_REQUIRE([AC_PROG_SED])
 AC_LANG_PUSH([C])
 ax_pthread_ok=no
 
 # We used to check for pthread.h first, but this fails if pthread.h
-# requires special compiler flags (e.g. on True64 or Sequent).
+# requires special compiler flags (e.g. on Tru64 or Sequent).
 # It gets checked for in the link test anyway.
 
 # First of all, check if the user has set any of the PTHREAD_LIBS,
 # etcetera environment variables, and if threads linking works using
 # them:
-if test x"$PTHREAD_LIBS$PTHREAD_CFLAGS" != x; then
-        save_CFLAGS="$CFLAGS"
-        CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
-        save_LIBS="$LIBS"
-        LIBS="$PTHREAD_LIBS $LIBS"
-        AC_MSG_CHECKING([for pthread_join in LIBS=$PTHREAD_LIBS with CFLAGS=$PTHREAD_CFLAGS])
-        AC_TRY_LINK_FUNC([pthread_join], [ax_pthread_ok=yes])
-        AC_MSG_RESULT([$ax_pthread_ok])
-        if test x"$ax_pthread_ok" = xno; then
-                PTHREAD_LIBS=""
-                PTHREAD_CFLAGS=""
-        fi
-        LIBS="$save_LIBS"
-        CFLAGS="$save_CFLAGS"
+if test "x$PTHREAD_CFLAGS$PTHREAD_LIBS" != "x"; then
+	ax_pthread_save_CC="$CC"
+	ax_pthread_save_CFLAGS="$CFLAGS"
+	ax_pthread_save_LIBS="$LIBS"
+	AS_IF([test "x$PTHREAD_CC" != "x"], [CC="$PTHREAD_CC"])
+	CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
+	LIBS="$PTHREAD_LIBS $LIBS"
+	AC_MSG_CHECKING([for pthread_join using $CC $PTHREAD_CFLAGS $PTHREAD_LIBS])
+	AC_LINK_IFELSE([AC_LANG_CALL([], [pthread_join])], [ax_pthread_ok=yes])
+	AC_MSG_RESULT([$ax_pthread_ok])
+	if test "x$ax_pthread_ok" = "xno"; then
+		PTHREAD_LIBS=""
+		PTHREAD_CFLAGS=""
+	fi
+	CC="$ax_pthread_save_CC"
+	CFLAGS="$ax_pthread_save_CFLAGS"
+	LIBS="$ax_pthread_save_LIBS"
 fi
 
 # We must check for the threads library under a number of different
@@ -123,7 +128,7 @@ fi
 # which indicates that we try without any flags at all, and "pthread-config"
 # which is a program returning the flags for the Pth emulation library.
 
-ax_pthread_flags="pthreads none -Kthread -kthread lthread -pthread -pthreads -mthreads pthread --thread-safe -mt pthread-config"
+ax_pthread_flags="pthreads none -Kthread -pthread -pthreads -mthreads pthread --thread-safe -mt pthread-config"
 
 # The ordering *is* (sometimes) important.  Some notes on the
 # individual items follow:
@@ -132,186 +137,334 @@ ax_pthread_flags="pthreads none -Kthread -kthread lthread -pthread -pthreads -mt
 # none: in case threads are in libc; should be tried before -Kthread and
 #       other compiler flags to prevent continual compiler warnings
 # -Kthread: Sequent (threads in libc, but -Kthread needed for pthread.h)
-# -kthread: FreeBSD kernel threads (preferred to -pthread since SMP-able)
-# lthread: LinuxThreads port on FreeBSD (also preferred to -pthread)
-# -pthread: Linux/gcc (kernel threads), BSD/gcc (userland threads)
-# -pthreads: Solaris/gcc
-# -mthreads: Mingw32/gcc, Lynx/gcc
+# -pthread: Linux/gcc (kernel threads), BSD/gcc (userland threads), Tru64
+#           (Note: HP C rejects this with "bad form for `-t' option")
+# -pthreads: Solaris/gcc (Note: HP C also rejects)
 # -mt: Sun Workshop C (may only link SunOS threads [-lthread], but it
-#      doesn't hurt to check since this sometimes defines pthreads too;
-#      also defines -D_REENTRANT)
-#      ... -mt is also the pthreads flag for HP/aCC
+#      doesn't hurt to check since this sometimes defines pthreads and
+#      -D_REENTRANT too), HP C (must be checked before -lpthread, which
+#      is present but should not be used directly; and before -mthreads,
+#      because the compiler interprets this as "-mt" + "-hreads")
+# -mthreads: Mingw32/gcc, Lynx/gcc
 # pthread: Linux, etcetera
 # --thread-safe: KAI C++
 # pthread-config: use pthread-config program (for GNU Pth library)
 
-case ${host_os} in
-        solaris*)
+case $host_os in
+
+	freebsd*)
+
+	# -kthread: FreeBSD kernel threads (preferred to -pthread since SMP-able)
+	# lthread: LinuxThreads port on FreeBSD (also preferred to -pthread)
+
+	ax_pthread_flags="-kthread lthread $ax_pthread_flags"
+	;;
+
+	hpux*)
+
+	# From the cc(1) man page: "[-mt] Sets various -D flags to enable
+	# multi-threading and also sets -lpthread."
+
+	ax_pthread_flags="-mt -pthread pthread $ax_pthread_flags"
+	;;
+
+	openedition*)
 
-        # On Solaris (at least, for some versions), libc contains stubbed
-        # (non-functional) versions of the pthreads routines, so link-based
-        # tests will erroneously succeed.  (We need to link with -pthreads/-mt/
-        # -lpthread.)  (The stubs are missing pthread_cleanup_push, or rather
-        # a function called by this macro, so we could check for that, but
-        # who knows whether they'll stub that too in a future libc.)  So,
-        # we'll just look for -pthreads and -lpthread first:
+	# IBM z/OS requires a feature-test macro to be defined in order to
+	# enable POSIX threads at all, so give the user a hint if this is
+	# not set. (We don't define these ourselves, as they can affect
+	# other portions of the system API in unpredictable ways.)
 
-        ax_pthread_flags="-pthreads pthread -mt -pthread $ax_pthread_flags"
-        ;;
+	AC_EGREP_CPP([AX_PTHREAD_ZOS_MISSING],
+	    [
+#	     if !defined(_OPEN_THREADS) && !defined(_UNIX03_THREADS)
+	     AX_PTHREAD_ZOS_MISSING
+#	     endif
+	    ],
+	    [AC_MSG_WARN([IBM z/OS requires -D_OPEN_THREADS or -D_UNIX03_THREADS to enable pthreads support.])])
+	;;
 
-        darwin*)
-        ax_pthread_flags="-pthread $ax_pthread_flags"
-        ;;
+	solaris*)
+
+	# On Solaris (at least, for some versions), libc contains stubbed
+	# (non-functional) versions of the pthreads routines, so link-based
+	# tests will erroneously succeed. (N.B.: The stubs are missing
+	# pthread_cleanup_push, or rather a function called by this macro,
+	# so we could check for that, but who knows whether they'll stub
+	# that too in a future libc.)  So we'll check first for the
+	# standard Solaris way of linking pthreads (-mt -lpthread).
+
+	ax_pthread_flags="-mt,pthread pthread $ax_pthread_flags"
+	;;
 esac
 
-# Clang doesn't consider unrecognized options an error unless we specify
-# -Werror. We throw in some extra Clang-specific options to ensure that
-# this doesn't happen for GCC, which also accepts -Werror.
-
-AC_MSG_CHECKING([if compiler needs -Werror to reject unknown flags])
-save_CFLAGS="$CFLAGS"
-ax_pthread_extra_flags="-Werror"
-CFLAGS="$CFLAGS $ax_pthread_extra_flags -Wunknown-warning-option -Wsizeof-array-argument"
-AC_COMPILE_IFELSE([AC_LANG_PROGRAM([int foo(void);],[foo()])],
-                  [AC_MSG_RESULT([yes])],
-                  [ax_pthread_extra_flags=
-                   AC_MSG_RESULT([no])])
-CFLAGS="$save_CFLAGS"
-
-if test x"$ax_pthread_ok" = xno; then
-for flag in $ax_pthread_flags; do
-
-        case $flag in
-                none)
-                AC_MSG_CHECKING([whether pthreads work without any flags])
-                ;;
-
-                -*)
-                AC_MSG_CHECKING([whether pthreads work with $flag])
-                PTHREAD_CFLAGS="$flag"
-                ;;
-
-                pthread-config)
-                AC_CHECK_PROG([ax_pthread_config], [pthread-config], [yes], [no])
-                if test x"$ax_pthread_config" = xno; then continue; fi
-                PTHREAD_CFLAGS="`pthread-config --cflags`"
-                PTHREAD_LIBS="`pthread-config --ldflags` `pthread-config --libs`"
-                ;;
-
-                *)
-                AC_MSG_CHECKING([for the pthreads library -l$flag])
-                PTHREAD_LIBS="-l$flag"
-                ;;
-        esac
-
-        save_LIBS="$LIBS"
-        save_CFLAGS="$CFLAGS"
-        LIBS="$PTHREAD_LIBS $LIBS"
-        CFLAGS="$CFLAGS $PTHREAD_CFLAGS $ax_pthread_extra_flags"
-
-        # Check for various functions.  We must include pthread.h,
-        # since some functions may be macros.  (On the Sequent, we
-        # need a special flag -Kthread to make this header compile.)
-        # We check for pthread_join because it is in -lpthread on IRIX
-        # while pthread_create is in libc.  We check for pthread_attr_init
-        # due to DEC craziness with -lpthreads.  We check for
-        # pthread_cleanup_push because it is one of the few pthread
-        # functions on Solaris that doesn't have a non-functional libc stub.
-        # We try pthread_create on general principles.
-        AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <pthread.h>
-                        static void routine(void *a) { a = 0; }
-                        static void *start_routine(void *a) { return a; }],
-                       [pthread_t th; pthread_attr_t attr;
-                        pthread_create(&th, 0, start_routine, 0);
-                        pthread_join(th, 0);
-                        pthread_attr_init(&attr);
-                        pthread_cleanup_push(routine, 0);
-                        pthread_cleanup_pop(0) /* ; */])],
-                [ax_pthread_ok=yes],
-                [])
-
-        LIBS="$save_LIBS"
-        CFLAGS="$save_CFLAGS"
-
-        AC_MSG_RESULT([$ax_pthread_ok])
-        if test "x$ax_pthread_ok" = xyes; then
-                break;
-        fi
-
-        PTHREAD_LIBS=""
-        PTHREAD_CFLAGS=""
+# GCC generally uses -pthread, or -pthreads on some platforms (e.g. SPARC)
+
+AS_IF([test "x$GCC" = "xyes"],
+      [ax_pthread_flags="-pthread -pthreads $ax_pthread_flags"])
+
+# The presence of a feature test macro requesting re-entrant function
+# definitions is, on some systems, a strong hint that pthreads support is
+# correctly enabled
+
+case $host_os in
+	darwin* | hpux* | linux* | osf* | solaris*)
+	ax_pthread_check_macro="_REENTRANT"
+	;;
+
+	aix* | freebsd*)
+	ax_pthread_check_macro="_THREAD_SAFE"
+	;;
+
+	*)
+	ax_pthread_check_macro="--"
+	;;
+esac
+AS_IF([test "x$ax_pthread_check_macro" = "x--"],
+      [ax_pthread_check_cond=0],
+      [ax_pthread_check_cond="!defined($ax_pthread_check_macro)"])
+
+# Are we compiling with Clang?
+
+AC_CACHE_CHECK([whether $CC is Clang],
+    [ax_cv_PTHREAD_CLANG],
+    [ax_cv_PTHREAD_CLANG=no
+     # Note that Autoconf sets GCC=yes for Clang as well as GCC
+     if test "x$GCC" = "xyes"; then
+	AC_EGREP_CPP([AX_PTHREAD_CC_IS_CLANG],
+	    [/* Note: Clang 2.7 lacks __clang_[a-z]+__ */
+#	     if defined(__clang__) && defined(__llvm__)
+	     AX_PTHREAD_CC_IS_CLANG
+#	     endif
+	    ],
+	    [ax_cv_PTHREAD_CLANG=yes])
+     fi
+    ])
+ax_pthread_clang="$ax_cv_PTHREAD_CLANG"
+
+ax_pthread_clang_warning=no
+
+# Clang needs special handling, because older versions handle the -pthread
+# option in a rather... idiosyncratic way
+
+if test "x$ax_pthread_clang" = "xyes"; then
+
+	# Clang takes -pthread; it has never supported any other flag
+
+	# (Note 1: This will need to be revisited if a system that Clang
+	# supports has POSIX threads in a separate library.  This tends not
+	# to be the way of modern systems, but it's conceivable.)
+
+	# (Note 2: On some systems, notably Darwin, -pthread is not needed
+	# to get POSIX threads support; the API is always present and
+	# active.  We could reasonably leave PTHREAD_CFLAGS empty.  But
+	# -pthread does define _REENTRANT, and while the Darwin headers
+	# ignore this macro, third-party headers might not.)
+
+	PTHREAD_CFLAGS="-pthread"
+	PTHREAD_LIBS=
+
+	ax_pthread_ok=yes
+
+	# However, older versions of Clang make a point of warning the user
+	# that, in an invocation where only linking and no compilation is
+	# taking place, the -pthread option has no effect ("argument unused
+	# during compilation").  They expect -pthread to be passed in only
+	# when source code is being compiled.
+	#
+	# Problem is, this is at odds with the way Automake and most other
+	# C build frameworks function, which is that the same flags used in
+	# compilation (CFLAGS) are also used in linking.  Many systems
+	# supported by AX_PTHREAD require exactly this for POSIX threads
+	# support, and in fact it is often not straightforward to specify a
+	# flag that is used only in the compilation phase and not in
+	# linking.  Such a scenario is extremely rare in practice.
+	#
+	# Even though use of the -pthread flag in linking would only print
+	# a warning, this can be a nuisance for well-run software projects
+	# that build with -Werror.  So if the active version of Clang has
+	# this misfeature, we search for an option to squash it.
+
+	AC_CACHE_CHECK([whether Clang needs flag to prevent "argument unused" warning when linking with -pthread],
+	    [ax_cv_PTHREAD_CLANG_NO_WARN_FLAG],
+	    [ax_cv_PTHREAD_CLANG_NO_WARN_FLAG=unknown
+	     # Create an alternate version of $ac_link that compiles and
+	     # links in two steps (.c -> .o, .o -> exe) instead of one
+	     # (.c -> exe), because the warning occurs only in the second
+	     # step
+	     ax_pthread_save_ac_link="$ac_link"
+	     ax_pthread_sed='s/conftest\.\$ac_ext/conftest.$ac_objext/g'
+	     ax_pthread_link_step=`$as_echo "$ac_link" | sed "$ax_pthread_sed"`
+	     ax_pthread_2step_ac_link="($ac_compile) && (echo ==== >&5) && ($ax_pthread_link_step)"
+	     ax_pthread_save_CFLAGS="$CFLAGS"
+	     for ax_pthread_try in '' -Qunused-arguments -Wno-unused-command-line-argument unknown; do
+		AS_IF([test "x$ax_pthread_try" = "xunknown"], [break])
+		CFLAGS="-Werror -Wunknown-warning-option $ax_pthread_try -pthread $ax_pthread_save_CFLAGS"
+		ac_link="$ax_pthread_save_ac_link"
+		AC_LINK_IFELSE([AC_LANG_SOURCE([[int main(void){return 0;}]])],
+		    [ac_link="$ax_pthread_2step_ac_link"
+		     AC_LINK_IFELSE([AC_LANG_SOURCE([[int main(void){return 0;}]])],
+			 [break])
+		    ])
+	     done
+	     ac_link="$ax_pthread_save_ac_link"
+	     CFLAGS="$ax_pthread_save_CFLAGS"
+	     AS_IF([test "x$ax_pthread_try" = "x"], [ax_pthread_try=no])
+	     ax_cv_PTHREAD_CLANG_NO_WARN_FLAG="$ax_pthread_try"
+	    ])
+
+	case "$ax_cv_PTHREAD_CLANG_NO_WARN_FLAG" in
+		no | unknown) ;;
+		*) PTHREAD_CFLAGS="$ax_cv_PTHREAD_CLANG_NO_WARN_FLAG $PTHREAD_CFLAGS" ;;
+	esac
+
+fi # $ax_pthread_clang = yes
+
+if test "x$ax_pthread_ok" = "xno"; then
+for ax_pthread_try_flag in $ax_pthread_flags; do
+
+	case $ax_pthread_try_flag in
+		none)
+		AC_MSG_CHECKING([whether pthreads work without any flags])
+		;;
+
+		-mt,pthread)
+		AC_MSG_CHECKING([whether pthreads work with -mt -lpthread])
+		PTHREAD_CFLAGS="-mt"
+		PTHREAD_LIBS="-lpthread"
+		;;
+
+		-*)
+		AC_MSG_CHECKING([whether pthreads work with $ax_pthread_try_flag])
+		PTHREAD_CFLAGS="$ax_pthread_try_flag"
+		;;
+
+		pthread-config)
+		AC_CHECK_PROG([ax_pthread_config], [pthread-config], [yes], [no])
+		AS_IF([test "x$ax_pthread_config" = "xno"], [continue])
+		PTHREAD_CFLAGS="`pthread-config --cflags`"
+		PTHREAD_LIBS="`pthread-config --ldflags` `pthread-config --libs`"
+		;;
+
+		*)
+		AC_MSG_CHECKING([for the pthreads library -l$ax_pthread_try_flag])
+		PTHREAD_LIBS="-l$ax_pthread_try_flag"
+		;;
+	esac
+
+	ax_pthread_save_CFLAGS="$CFLAGS"
+	ax_pthread_save_LIBS="$LIBS"
+	CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
+	LIBS="$PTHREAD_LIBS $LIBS"
+
+	# Check for various functions.  We must include pthread.h,
+	# since some functions may be macros.  (On the Sequent, we
+	# need a special flag -Kthread to make this header compile.)
+	# We check for pthread_join because it is in -lpthread on IRIX
+	# while pthread_create is in libc.  We check for pthread_attr_init
+	# due to DEC craziness with -lpthreads.  We check for
+	# pthread_cleanup_push because it is one of the few pthread
+	# functions on Solaris that doesn't have a non-functional libc stub.
+	# We try pthread_create on general principles.
+
+	AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <pthread.h>
+#			if $ax_pthread_check_cond
+#			 error "$ax_pthread_check_macro must be defined"
+#			endif
+			static void routine(void *a) { a = 0; }
+			static void *start_routine(void *a) { return a; }],
+		       [pthread_t th; pthread_attr_t attr;
+			pthread_create(&th, 0, start_routine, 0);
+			pthread_join(th, 0);
+			pthread_attr_init(&attr);
+			pthread_cleanup_push(routine, 0);
+			pthread_cleanup_pop(0) /* ; */])],
+	    [ax_pthread_ok=yes],
+	    [])
+
+	CFLAGS="$ax_pthread_save_CFLAGS"
+	LIBS="$ax_pthread_save_LIBS"
+
+	AC_MSG_RESULT([$ax_pthread_ok])
+	AS_IF([test "x$ax_pthread_ok" = "xyes"], [break])
+
+	PTHREAD_LIBS=""
+	PTHREAD_CFLAGS=""
 done
 fi
 
 # Various other checks:
-if test "x$ax_pthread_ok" = xyes; then
-        save_LIBS="$LIBS"
-        LIBS="$PTHREAD_LIBS $LIBS"
-        save_CFLAGS="$CFLAGS"
-        CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
-
-        # Detect AIX lossage: JOINABLE attribute is called UNDETACHED.
-        AC_MSG_CHECKING([for joinable pthread attribute])
-        attr_name=unknown
-        for attr in PTHREAD_CREATE_JOINABLE PTHREAD_CREATE_UNDETACHED; do
-            AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <pthread.h>],
-                           [int attr = $attr; return attr /* ; */])],
-                [attr_name=$attr; break],
-                [])
-        done
-        AC_MSG_RESULT([$attr_name])
-        if test "$attr_name" != PTHREAD_CREATE_JOINABLE; then
-            AC_DEFINE_UNQUOTED([PTHREAD_CREATE_JOINABLE], [$attr_name],
-                               [Define to necessary symbol if this constant
-                                uses a non-standard name on your system.])
-        fi
-
-        AC_MSG_CHECKING([if more special flags are required for pthreads])
-        flag=no
-        case ${host_os} in
-            aix* | freebsd* | darwin*) flag="-D_THREAD_SAFE";;
-            osf* | hpux*) flag="-D_REENTRANT";;
-            solaris*)
-            if test "$GCC" = "yes"; then
-                flag="-D_REENTRANT"
-            else
-                # TODO: What about Clang on Solaris?
-                flag="-mt -D_REENTRANT"
-            fi
-            ;;
-        esac
-        AC_MSG_RESULT([$flag])
-        if test "x$flag" != xno; then
-            PTHREAD_CFLAGS="$flag $PTHREAD_CFLAGS"
-        fi
-
-        AC_CACHE_CHECK([for PTHREAD_PRIO_INHERIT],
-            [ax_cv_PTHREAD_PRIO_INHERIT], [
-                AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <pthread.h>]],
-                                                [[int i = PTHREAD_PRIO_INHERIT;]])],
-                    [ax_cv_PTHREAD_PRIO_INHERIT=yes],
-                    [ax_cv_PTHREAD_PRIO_INHERIT=no])
-            ])
-        AS_IF([test "x$ax_cv_PTHREAD_PRIO_INHERIT" = "xyes"],
-            [AC_DEFINE([HAVE_PTHREAD_PRIO_INHERIT], [1], [Have PTHREAD_PRIO_INHERIT.])])
-
-        LIBS="$save_LIBS"
-        CFLAGS="$save_CFLAGS"
-
-        # More AIX lossage: compile with *_r variant
-        if test "x$GCC" != xyes; then
-            case $host_os in
-                aix*)
-                AS_CASE(["x/$CC"],
-                  [x*/c89|x*/c89_128|x*/c99|x*/c99_128|x*/cc|x*/cc128|x*/xlc|x*/xlc_v6|x*/xlc128|x*/xlc128_v6],
-                  [#handle absolute path differently from PATH based program lookup
-                   AS_CASE(["x$CC"],
-                     [x/*],
-                     [AS_IF([AS_EXECUTABLE_P([${CC}_r])],[PTHREAD_CC="${CC}_r"])],
-                     [AC_CHECK_PROGS([PTHREAD_CC],[${CC}_r],[$CC])])])
-                ;;
-            esac
-        fi
+if test "x$ax_pthread_ok" = "xyes"; then
+	ax_pthread_save_CFLAGS="$CFLAGS"
+	ax_pthread_save_LIBS="$LIBS"
+	CFLAGS="$CFLAGS $PTHREAD_CFLAGS"
+	LIBS="$PTHREAD_LIBS $LIBS"
+
+	# Detect AIX lossage: JOINABLE attribute is called UNDETACHED.
+	AC_CACHE_CHECK([for joinable pthread attribute],
+	    [ax_cv_PTHREAD_JOINABLE_ATTR],
+	    [ax_cv_PTHREAD_JOINABLE_ATTR=unknown
+	     for ax_pthread_attr in PTHREAD_CREATE_JOINABLE PTHREAD_CREATE_UNDETACHED; do
+		 AC_LINK_IFELSE([AC_LANG_PROGRAM([#include <pthread.h>],
+						 [int attr = $ax_pthread_attr; return attr /* ; */])],
+				[ax_cv_PTHREAD_JOINABLE_ATTR=$ax_pthread_attr; break],
+				[])
+	     done
+	    ])
+	AS_IF([test "x$ax_cv_PTHREAD_JOINABLE_ATTR" != "xunknown" && \
+	       test "x$ax_cv_PTHREAD_JOINABLE_ATTR" != "xPTHREAD_CREATE_JOINABLE" && \
+	       test "x$ax_pthread_joinable_attr_defined" != "xyes"],
+	      [AC_DEFINE_UNQUOTED([PTHREAD_CREATE_JOINABLE],
+				  [$ax_cv_PTHREAD_JOINABLE_ATTR],
+				  [Define to necessary symbol if this constant
+				   uses a non-standard name on your system.])
+	       ax_pthread_joinable_attr_defined=yes
+	      ])
+
+	AC_CACHE_CHECK([whether more special flags are required for pthreads],
+	    [ax_cv_PTHREAD_SPECIAL_FLAGS],
+	    [ax_cv_PTHREAD_SPECIAL_FLAGS=no
+	     case $host_os in
+	     solaris*)
+	     ax_cv_PTHREAD_SPECIAL_FLAGS="-D_POSIX_PTHREAD_SEMANTICS"
+	     ;;
+	     esac
+	    ])
+	AS_IF([test "x$ax_cv_PTHREAD_SPECIAL_FLAGS" != "xno" && \
+	       test "x$ax_pthread_special_flags_added" != "xyes"],
+	      [PTHREAD_CFLAGS="$ax_cv_PTHREAD_SPECIAL_FLAGS $PTHREAD_CFLAGS"
+	       ax_pthread_special_flags_added=yes])
+
+	AC_CACHE_CHECK([for PTHREAD_PRIO_INHERIT],
+	    [ax_cv_PTHREAD_PRIO_INHERIT],
+	    [AC_LINK_IFELSE([AC_LANG_PROGRAM([[#include <pthread.h>]],
+					     [[int i = PTHREAD_PRIO_INHERIT;]])],
+			    [ax_cv_PTHREAD_PRIO_INHERIT=yes],
+			    [ax_cv_PTHREAD_PRIO_INHERIT=no])
+	    ])
+	AS_IF([test "x$ax_cv_PTHREAD_PRIO_INHERIT" = "xyes" && \
+	       test "x$ax_pthread_prio_inherit_defined" != "xyes"],
+	      [AC_DEFINE([HAVE_PTHREAD_PRIO_INHERIT], [1], [Have PTHREAD_PRIO_INHERIT.])
+	       ax_pthread_prio_inherit_defined=yes
+	      ])
+
+	CFLAGS="$ax_pthread_save_CFLAGS"
+	LIBS="$ax_pthread_save_LIBS"
+
+	# More AIX lossage: compile with *_r variant
+	if test "x$GCC" != "xyes"; then
+	    case $host_os in
+		aix*)
+		AS_CASE(["x/$CC"],
+		    [x*/c89|x*/c89_128|x*/c99|x*/c99_128|x*/cc|x*/cc128|x*/xlc|x*/xlc_v6|x*/xlc128|x*/xlc128_v6],
+		    [#handle absolute path differently from PATH based program lookup
+		     AS_CASE(["x$CC"],
+			 [x/*],
+			 [AS_IF([AS_EXECUTABLE_P([${CC}_r])],[PTHREAD_CC="${CC}_r"])],
+			 [AC_CHECK_PROGS([PTHREAD_CC],[${CC}_r],[$CC])])])
+		;;
+	    esac
+	fi
 fi
 
 test -n "$PTHREAD_CC" || PTHREAD_CC="$CC"
@@ -321,12 +474,12 @@ AC_SUBST([PTHREAD_CFLAGS])
 AC_SUBST([PTHREAD_CC])
 
 # Finally, execute ACTION-IF-FOUND/ACTION-IF-NOT-FOUND:
-if test x"$ax_pthread_ok" = xyes; then
-        ifelse([$1],,[AC_DEFINE([HAVE_PTHREAD],[1],[Define if you have POSIX threads libraries and header files.])],[$1])
-        :
+if test "x$ax_pthread_ok" = "xyes"; then
+	ifelse([$1],,[AC_DEFINE([HAVE_PTHREAD],[1],[Define if you have POSIX threads libraries and header files.])],[$1])
+	:
 else
-        ax_pthread_ok=no
-        $2
+	ax_pthread_ok=no
+	$2
 fi
 AC_LANG_POP
 ])dnl AX_PTHREAD