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			12 KiB
		
	
	
	
		
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			317 lines
		
	
	
		
			12 KiB
		
	
	
	
		
			Plaintext
		
	
	
| # lock.m4 serial 7 (gettext-0.17)
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| dnl Copyright (C) 2005-2007 Free Software Foundation, Inc.
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| dnl This file is free software; the Free Software Foundation
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| dnl gives unlimited permission to copy and/or distribute it,
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| dnl with or without modifications, as long as this notice is preserved.
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| 
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| dnl From Bruno Haible.
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| 
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| dnl Tests for a multithreading library to be used.
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| dnl Defines at most one of the macros USE_POSIX_THREADS, USE_SOLARIS_THREADS,
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| dnl USE_PTH_THREADS, USE_WIN32_THREADS
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| dnl Sets the variables LIBTHREAD and LTLIBTHREAD to the linker options for use
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| dnl in a Makefile (LIBTHREAD for use without libtool, LTLIBTHREAD for use with
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| dnl libtool).
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| dnl Sets the variables LIBMULTITHREAD and LTLIBMULTITHREAD similarly, for
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| dnl programs that really need multithread functionality. The difference
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| dnl between LIBTHREAD and LIBMULTITHREAD is that on platforms supporting weak
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| dnl symbols, typically LIBTHREAD="" whereas LIBMULTITHREAD="-lpthread".
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| dnl Adds to CPPFLAGS the flag -D_REENTRANT or -D_THREAD_SAFE if needed for
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| dnl multithread-safe programs.
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| 
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| AC_DEFUN([gl_LOCK_EARLY],
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| [
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|   AC_REQUIRE([gl_LOCK_EARLY_BODY])
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| ])
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| 
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| dnl The guts of gl_LOCK_EARLY. Needs to be expanded only once.
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| 
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| AC_DEFUN([gl_LOCK_EARLY_BODY],
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| [
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|   dnl Ordering constraints: This macro modifies CPPFLAGS in a way that
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|   dnl influences the result of the autoconf tests that test for *_unlocked
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|   dnl declarations, on AIX 5 at least. Therefore it must come early.
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|   AC_BEFORE([$0], [gl_FUNC_GLIBC_UNLOCKED_IO])dnl
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|   AC_BEFORE([$0], [gl_ARGP])dnl
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| 
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|   AC_REQUIRE([AC_CANONICAL_HOST])
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|   dnl _GNU_SOURCE is needed for pthread_rwlock_t on glibc systems.
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|   dnl AC_USE_SYSTEM_EXTENSIONS was introduced in autoconf 2.60 and obsoletes
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|   dnl AC_GNU_SOURCE.
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|   m4_ifdef([AC_USE_SYSTEM_EXTENSIONS],
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|     [AC_REQUIRE([AC_USE_SYSTEM_EXTENSIONS])],
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|     [AC_REQUIRE([AC_GNU_SOURCE])])
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|   dnl Check for multithreading.
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|   AC_ARG_ENABLE(threads,
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| AC_HELP_STRING([--enable-threads={posix|solaris|pth|win32}], [specify multithreading API])
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| AC_HELP_STRING([--disable-threads], [build without multithread safety]),
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|     [gl_use_threads=$enableval],
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|     [case "$host_os" in
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|        dnl Disable multithreading by default on OSF/1, because it interferes
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|        dnl with fork()/exec(): When msgexec is linked with -lpthread, its child
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|        dnl process gets an endless segmentation fault inside execvp().
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|        osf*) gl_use_threads=no ;;
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|        *)    gl_use_threads=yes ;;
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|      esac
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|     ])
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|   if test "$gl_use_threads" = yes || test "$gl_use_threads" = posix; then
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|     # For using <pthread.h>:
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|     case "$host_os" in
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|       osf*)
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|         # On OSF/1, the compiler needs the flag -D_REENTRANT so that it
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|         # groks <pthread.h>. cc also understands the flag -pthread, but
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|         # we don't use it because 1. gcc-2.95 doesn't understand -pthread,
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|         # 2. putting a flag into CPPFLAGS that has an effect on the linker
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|         # causes the AC_TRY_LINK test below to succeed unexpectedly,
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|         # leading to wrong values of LIBTHREAD and LTLIBTHREAD.
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|         CPPFLAGS="$CPPFLAGS -D_REENTRANT"
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|         ;;
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|     esac
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|     # Some systems optimize for single-threaded programs by default, and
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|     # need special flags to disable these optimizations. For example, the
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|     # definition of 'errno' in <errno.h>.
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|     case "$host_os" in
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|       aix* | freebsd*) CPPFLAGS="$CPPFLAGS -D_THREAD_SAFE" ;;
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|       solaris*) CPPFLAGS="$CPPFLAGS -D_REENTRANT" ;;
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|     esac
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|   fi
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| ])
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| 
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| dnl The guts of gl_LOCK. Needs to be expanded only once.
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| 
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| AC_DEFUN([gl_LOCK_BODY],
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| [
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|   AC_REQUIRE([gl_LOCK_EARLY_BODY])
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|   gl_threads_api=none
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|   LIBTHREAD=
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|   LTLIBTHREAD=
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|   LIBMULTITHREAD=
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|   LTLIBMULTITHREAD=
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|   if test "$gl_use_threads" != no; then
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|     dnl Check whether the compiler and linker support weak declarations.
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|     AC_MSG_CHECKING([whether imported symbols can be declared weak])
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|     gl_have_weak=no
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|     AC_TRY_LINK([extern void xyzzy ();
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| #pragma weak xyzzy], [xyzzy();], [gl_have_weak=yes])
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|     AC_MSG_RESULT([$gl_have_weak])
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|     if test "$gl_use_threads" = yes || test "$gl_use_threads" = posix; then
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|       # On OSF/1, the compiler needs the flag -pthread or -D_REENTRANT so that
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|       # it groks <pthread.h>. It's added above, in gl_LOCK_EARLY_BODY.
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|       AC_CHECK_HEADER(pthread.h, gl_have_pthread_h=yes, gl_have_pthread_h=no)
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|       if test "$gl_have_pthread_h" = yes; then
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|         # Other possible tests:
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|         #   -lpthreads (FSU threads, PCthreads)
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|         #   -lgthreads
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|         gl_have_pthread=
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|         # Test whether both pthread_mutex_lock and pthread_mutexattr_init exist
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|         # in libc. IRIX 6.5 has the first one in both libc and libpthread, but
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|         # the second one only in libpthread, and lock.c needs it.
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|         AC_TRY_LINK([#include <pthread.h>],
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|           [pthread_mutex_lock((pthread_mutex_t*)0);
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|            pthread_mutexattr_init((pthread_mutexattr_t*)0);],
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|           [gl_have_pthread=yes])
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|         # Test for libpthread by looking for pthread_kill. (Not pthread_self,
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|         # since it is defined as a macro on OSF/1.)
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|         if test -n "$gl_have_pthread"; then
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|           # The program links fine without libpthread. But it may actually
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|           # need to link with libpthread in order to create multiple threads.
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|           AC_CHECK_LIB(pthread, pthread_kill,
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|             [LIBMULTITHREAD=-lpthread LTLIBMULTITHREAD=-lpthread
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|              # On Solaris and HP-UX, most pthread functions exist also in libc.
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|              # Therefore pthread_in_use() needs to actually try to create a
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|              # thread: pthread_create from libc will fail, whereas
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|              # pthread_create will actually create a thread.
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|              case "$host_os" in
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|                solaris* | hpux*)
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|                  AC_DEFINE([PTHREAD_IN_USE_DETECTION_HARD], 1,
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|                    [Define if the pthread_in_use() detection is hard.])
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|              esac
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|             ])
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|         else
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|           # Some library is needed. Try libpthread and libc_r.
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|           AC_CHECK_LIB(pthread, pthread_kill,
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|             [gl_have_pthread=yes
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|              LIBTHREAD=-lpthread LTLIBTHREAD=-lpthread
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|              LIBMULTITHREAD=-lpthread LTLIBMULTITHREAD=-lpthread])
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|           if test -z "$gl_have_pthread"; then
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|             # For FreeBSD 4.
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|             AC_CHECK_LIB(c_r, pthread_kill,
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|               [gl_have_pthread=yes
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|                LIBTHREAD=-lc_r LTLIBTHREAD=-lc_r
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|                LIBMULTITHREAD=-lc_r LTLIBMULTITHREAD=-lc_r])
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|           fi
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|         fi
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|         if test -n "$gl_have_pthread"; then
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|           gl_threads_api=posix
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|           AC_DEFINE([USE_POSIX_THREADS], 1,
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|             [Define if the POSIX multithreading library can be used.])
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|           if test -n "$LIBMULTITHREAD" || test -n "$LTLIBMULTITHREAD"; then
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|             if test $gl_have_weak = yes; then
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|               AC_DEFINE([USE_POSIX_THREADS_WEAK], 1,
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|                 [Define if references to the POSIX multithreading library should be made weak.])
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|               LIBTHREAD=
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|               LTLIBTHREAD=
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|             fi
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|           fi
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|           # OSF/1 4.0 and MacOS X 10.1 lack the pthread_rwlock_t type and the
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|           # pthread_rwlock_* functions.
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|           AC_CHECK_TYPE([pthread_rwlock_t],
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|             [AC_DEFINE([HAVE_PTHREAD_RWLOCK], 1,
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|                [Define if the POSIX multithreading library has read/write locks.])],
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|             [],
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|             [#include <pthread.h>])
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|           # glibc defines PTHREAD_MUTEX_RECURSIVE as enum, not as a macro.
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|           AC_TRY_COMPILE([#include <pthread.h>],
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|             [#if __FreeBSD__ == 4
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| error "No, in FreeBSD 4.0 recursive mutexes actually don't work."
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| #else
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| int x = (int)PTHREAD_MUTEX_RECURSIVE;
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| return !x;
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| #endif],
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|             [AC_DEFINE([HAVE_PTHREAD_MUTEX_RECURSIVE], 1,
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|                [Define if the <pthread.h> defines PTHREAD_MUTEX_RECURSIVE.])])
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|         fi
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|       fi
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|     fi
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|     if test -z "$gl_have_pthread"; then
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|       if test "$gl_use_threads" = yes || test "$gl_use_threads" = solaris; then
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|         gl_have_solaristhread=
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|         gl_save_LIBS="$LIBS"
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|         LIBS="$LIBS -lthread"
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|         AC_TRY_LINK([#include <thread.h>
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| #include <synch.h>],
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|           [thr_self();],
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|           [gl_have_solaristhread=yes])
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|         LIBS="$gl_save_LIBS"
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|         if test -n "$gl_have_solaristhread"; then
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|           gl_threads_api=solaris
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|           LIBTHREAD=-lthread
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|           LTLIBTHREAD=-lthread
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|           LIBMULTITHREAD="$LIBTHREAD"
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|           LTLIBMULTITHREAD="$LTLIBTHREAD"
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|           AC_DEFINE([USE_SOLARIS_THREADS], 1,
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|             [Define if the old Solaris multithreading library can be used.])
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|           if test $gl_have_weak = yes; then
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|             AC_DEFINE([USE_SOLARIS_THREADS_WEAK], 1,
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|               [Define if references to the old Solaris multithreading library should be made weak.])
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|             LIBTHREAD=
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|             LTLIBTHREAD=
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|           fi
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|         fi
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|       fi
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|     fi
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|     if test "$gl_use_threads" = pth; then
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|       gl_save_CPPFLAGS="$CPPFLAGS"
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|       AC_LIB_LINKFLAGS(pth)
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|       gl_have_pth=
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|       gl_save_LIBS="$LIBS"
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|       LIBS="$LIBS -lpth"
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|       AC_TRY_LINK([#include <pth.h>], [pth_self();], gl_have_pth=yes)
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|       LIBS="$gl_save_LIBS"
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|       if test -n "$gl_have_pth"; then
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|         gl_threads_api=pth
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|         LIBTHREAD="$LIBPTH"
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|         LTLIBTHREAD="$LTLIBPTH"
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|         LIBMULTITHREAD="$LIBTHREAD"
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|         LTLIBMULTITHREAD="$LTLIBTHREAD"
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|         AC_DEFINE([USE_PTH_THREADS], 1,
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|           [Define if the GNU Pth multithreading library can be used.])
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|         if test -n "$LIBMULTITHREAD" || test -n "$LTLIBMULTITHREAD"; then
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|           if test $gl_have_weak = yes; then
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|             AC_DEFINE([USE_PTH_THREADS_WEAK], 1,
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|               [Define if references to the GNU Pth multithreading library should be made weak.])
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|             LIBTHREAD=
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|             LTLIBTHREAD=
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|           fi
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|         fi
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|       else
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|         CPPFLAGS="$gl_save_CPPFLAGS"
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|       fi
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|     fi
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|     if test -z "$gl_have_pthread"; then
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|       if test "$gl_use_threads" = yes || test "$gl_use_threads" = win32; then
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|         if { case "$host_os" in
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|                mingw*) true;;
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|                *) false;;
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|              esac
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|            }; then
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|           gl_threads_api=win32
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|           AC_DEFINE([USE_WIN32_THREADS], 1,
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|             [Define if the Win32 multithreading API can be used.])
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|         fi
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|       fi
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|     fi
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|   fi
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|   AC_MSG_CHECKING([for multithread API to use])
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|   AC_MSG_RESULT([$gl_threads_api])
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|   AC_SUBST(LIBTHREAD)
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|   AC_SUBST(LTLIBTHREAD)
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|   AC_SUBST(LIBMULTITHREAD)
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|   AC_SUBST(LTLIBMULTITHREAD)
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| ])
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| 
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| AC_DEFUN([gl_LOCK],
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| [
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|   AC_REQUIRE([gl_LOCK_EARLY])
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|   AC_REQUIRE([gl_LOCK_BODY])
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|   gl_PREREQ_LOCK
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| ])
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| 
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| # Prerequisites of lib/lock.c.
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| AC_DEFUN([gl_PREREQ_LOCK], [
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|   AC_REQUIRE([AC_C_INLINE])
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| ])
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| 
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| dnl Survey of platforms:
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| dnl
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| dnl Platform          Available   Compiler    Supports   test-lock
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| dnl                   flavours    option      weak       result
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| dnl ---------------   ---------   ---------   --------   ---------
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| dnl Linux 2.4/glibc   posix       -lpthread       Y      OK
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| dnl
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| dnl GNU Hurd/glibc    posix
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| dnl
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| dnl FreeBSD 5.3       posix       -lc_r           Y
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| dnl                   posix       -lkse ?         Y
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| dnl                   posix       -lpthread ?     Y
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| dnl                   posix       -lthr           Y
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| dnl
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| dnl FreeBSD 5.2       posix       -lc_r           Y
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| dnl                   posix       -lkse           Y
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| dnl                   posix       -lthr           Y
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| dnl
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| dnl FreeBSD 4.0,4.10  posix       -lc_r           Y      OK
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| dnl
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| dnl NetBSD 1.6        --
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| dnl
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| dnl OpenBSD 3.4       posix       -lpthread       Y      OK
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| dnl
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| dnl MacOS X 10.[123]  posix       -lpthread       Y      OK
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| dnl
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| dnl Solaris 7,8,9     posix       -lpthread       Y      Sol 7,8: 0.0; Sol 9: OK
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| dnl                   solaris     -lthread        Y      Sol 7,8: 0.0; Sol 9: OK
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| dnl
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| dnl HP-UX 11          posix       -lpthread       N (cc) OK
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| dnl                                               Y (gcc)
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| dnl
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| dnl IRIX 6.5          posix       -lpthread       Y      0.5
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| dnl
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| dnl AIX 4.3,5.1       posix       -lpthread       N      AIX 4: 0.5; AIX 5: OK
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| dnl
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| dnl OSF/1 4.0,5.1     posix       -pthread (cc)   N      OK
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| dnl                               -lpthread (gcc) Y
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| dnl
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| dnl Cygwin            posix       -lpthread       Y      OK
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| dnl
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| dnl Any of the above  pth         -lpth                  0.0
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| dnl
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| dnl Mingw             win32                       N      OK
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| dnl
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| dnl BeOS 5            --
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| dnl
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| dnl The test-lock result shows what happens if in test-lock.c EXPLICIT_YIELD is
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| dnl turned off:
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| dnl   OK if all three tests terminate OK,
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| dnl   0.5 if the first test terminates OK but the second one loops endlessly,
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| dnl   0.0 if the first test already loops endlessly.
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