Update upstream source from tag 'upstream/1.9'
[debian/gzip] / m4 / threadlib.m4
index 9cedb67006511f581431f1fdb95400918d49abfc..1f7b1341c1e3fc2360171bdb4a1cf4fb433299a7 100644 (file)
@@ -1,5 +1,5 @@
-# threadlib.m4 serial 9 (gettext-0.18.2)
-dnl Copyright (C) 2005-2012 Free Software Foundation, Inc.
+# threadlib.m4 serial 13
+dnl Copyright (C) 2005-2018 Free Software Foundation, Inc.
 dnl This file is free software; the Free Software Foundation
 dnl gives unlimited permission to copy and/or distribute it,
 dnl with or without modifications, as long as this notice is preserved.
@@ -22,7 +22,7 @@ dnl libtool).
 dnl Sets the variables LIBMULTITHREAD and LTLIBMULTITHREAD similarly, for
 dnl programs that really need multithread functionality. The difference
 dnl between LIBTHREAD and LIBMULTITHREAD is that on platforms supporting weak
-dnl symbols, typically LIBTHREAD="" whereas LIBMULTITHREAD="-lpthread".
+dnl symbols, typically LIBTHREAD is empty whereas LIBMULTITHREAD is not.
 dnl Adds to CPPFLAGS the flag -D_REENTRANT or -D_THREAD_SAFE if needed for
 dnl multithread-safe programs.
 
@@ -66,7 +66,7 @@ changequote(,)dnl
          dnl child process gets an endless segmentation fault inside execvp().
          dnl Disable multithreading by default on Cygwin 1.5.x, because it has
          dnl bugs that lead to endless loops or crashes. See
-         dnl <http://cygwin.com/ml/cygwin/2009-08/msg00283.html>.
+         dnl <https://cygwin.com/ml/cygwin/2009-08/msg00283.html>.
          osf*) gl_use_threads=no ;;
          cygwin*)
                case `uname -r` in
@@ -148,6 +148,10 @@ int main ()
               [gl_cv_have_weak="guessing no"])
            ])
        fi
+       dnl But when linking statically, weak symbols don't work.
+       case " $LDFLAGS " in
+         *" -static "*) gl_cv_have_weak=no ;;
+       esac
       ])
     if test "$gl_use_threads" = yes || test "$gl_use_threads" = posix; then
       # On OSF/1, the compiler needs the flag -pthread or -D_REENTRANT so that
@@ -162,15 +166,31 @@ int main ()
         # Test whether both pthread_mutex_lock and pthread_mutexattr_init exist
         # in libc. IRIX 6.5 has the first one in both libc and libpthread, but
         # the second one only in libpthread, and lock.c needs it.
-        AC_LINK_IFELSE(
-          [AC_LANG_PROGRAM(
-             [[#include <pthread.h>]],
-             [[pthread_mutex_lock((pthread_mutex_t*)0);
-               pthread_mutexattr_init((pthread_mutexattr_t*)0);]])],
-          [gl_have_pthread=yes])
+        #
+        # If -pthread works, prefer it to -lpthread, since Ubuntu 14.04
+        # needs -pthread for some reason.  See:
+        # https://lists.gnu.org/r/bug-gnulib/2014-09/msg00023.html
+        save_LIBS=$LIBS
+        for gl_pthread in '' '-pthread'; do
+          LIBS="$LIBS $gl_pthread"
+          AC_LINK_IFELSE(
+            [AC_LANG_PROGRAM(
+               [[#include <pthread.h>
+                 pthread_mutex_t m;
+                 pthread_mutexattr_t ma;
+               ]],
+               [[pthread_mutex_lock (&m);
+                 pthread_mutexattr_init (&ma);]])],
+            [gl_have_pthread=yes
+             LIBTHREAD=$gl_pthread LTLIBTHREAD=$gl_pthread
+             LIBMULTITHREAD=$gl_pthread LTLIBMULTITHREAD=$gl_pthread])
+          LIBS=$save_LIBS
+          test -n "$gl_have_pthread" && break
+        done
+
         # Test for libpthread by looking for pthread_kill. (Not pthread_self,
         # since it is defined as a macro on OSF/1.)
-        if test -n "$gl_have_pthread"; then
+        if test -n "$gl_have_pthread" && test -z "$LIBTHREAD"; then
           # The program links fine without libpthread. But it may actually
           # need to link with libpthread in order to create multiple threads.
           AC_CHECK_LIB([pthread], [pthread_kill],
@@ -179,13 +199,15 @@ int main ()
              # Therefore pthread_in_use() needs to actually try to create a
              # thread: pthread_create from libc will fail, whereas
              # pthread_create will actually create a thread.
+             # On Solaris 10 or newer, this test is no longer needed, because
+             # libc contains the fully functional pthread functions.
              case "$host_os" in
-               solaris* | hpux*)
+               solaris | solaris2.[1-9] | solaris2.[1-9].* | hpux*)
                  AC_DEFINE([PTHREAD_IN_USE_DETECTION_HARD], [1],
                    [Define if the pthread_in_use() detection is hard.])
              esac
             ])
-        else
+        elif test -z "$gl_have_pthread"; then
           # Some library is needed. Try libpthread and libc_r.
           AC_CHECK_LIB([pthread], [pthread_kill],
             [gl_have_pthread=yes
@@ -319,50 +341,52 @@ AC_DEFUN([gl_DISABLE_THREADS], [
 
 dnl Survey of platforms:
 dnl
-dnl Platform          Available   Compiler    Supports   test-lock
-dnl                   flavours    option      weak       result
-dnl ---------------   ---------   ---------   --------   ---------
-dnl Linux 2.4/glibc   posix       -lpthread       Y      OK
+dnl Platform           Available  Compiler    Supports   test-lock
+dnl                    flavours   option      weak       result
+dnl ---------------    ---------  ---------   --------   ---------
+dnl Linux 2.4/glibc    posix      -lpthread       Y      OK
+dnl
+dnl GNU Hurd/glibc     posix
 dnl
-dnl GNU Hurd/glibc    posix
+dnl Ubuntu 14.04       posix      -pthread        Y      OK
 dnl
-dnl FreeBSD 5.3       posix       -lc_r           Y
-dnl                   posix       -lkse ?         Y
-dnl                   posix       -lpthread ?     Y
-dnl                   posix       -lthr           Y
+dnl FreeBSD 5.3        posix      -lc_r           Y
+dnl                    posix      -lkse ?         Y
+dnl                    posix      -lpthread ?     Y
+dnl                    posix      -lthr           Y
 dnl
-dnl FreeBSD 5.2       posix       -lc_r           Y
-dnl                   posix       -lkse           Y
-dnl                   posix       -lthr           Y
+dnl FreeBSD 5.2        posix      -lc_r           Y
+dnl                    posix      -lkse           Y
+dnl                    posix      -lthr           Y
 dnl
-dnl FreeBSD 4.0,4.10  posix       -lc_r           Y      OK
+dnl FreeBSD 4.0,4.10   posix      -lc_r           Y      OK
 dnl
-dnl NetBSD 1.6        --
+dnl NetBSD 1.6         --
 dnl
-dnl OpenBSD 3.4       posix       -lpthread       Y      OK
+dnl OpenBSD 3.4        posix      -lpthread       Y      OK
 dnl
-dnl MacOS X 10.[123]  posix       -lpthread       Y      OK
+dnl Mac OS X 10.[123]  posix      -lpthread       Y      OK
 dnl
-dnl Solaris 7,8,9     posix       -lpthread       Y      Sol 7,8: 0.0; Sol 9: OK
-dnl                   solaris     -lthread        Y      Sol 7,8: 0.0; Sol 9: OK
+dnl Solaris 7,8,9      posix      -lpthread       Y      Sol 7,8: 0.0; Sol 9: OK
+dnl                    solaris    -lthread        Y      Sol 7,8: 0.0; Sol 9: OK
 dnl
-dnl HP-UX 11          posix       -lpthread       N (cc) OK
+dnl HP-UX 11           posix      -lpthread       N (cc) OK
 dnl                                               Y (gcc)
 dnl
-dnl IRIX 6.5          posix       -lpthread       Y      0.5
+dnl IRIX 6.5           posix      -lpthread       Y      0.5
 dnl
-dnl AIX 4.3,5.1       posix       -lpthread       N      AIX 4: 0.5; AIX 5: OK
+dnl AIX 4.3,5.1        posix      -lpthread       N      AIX 4: 0.5; AIX 5: OK
 dnl
-dnl OSF/1 4.0,5.1     posix       -pthread (cc)   N      OK
+dnl OSF/1 4.0,5.1      posix      -pthread (cc)   N      OK
 dnl                               -lpthread (gcc) Y
 dnl
-dnl Cygwin            posix       -lpthread       Y      OK
+dnl Cygwin             posix      -lpthread       Y      OK
 dnl
-dnl Any of the above  pth         -lpth                  0.0
+dnl Any of the above   pth        -lpth                  0.0
 dnl
-dnl Mingw             windows                     N      OK
+dnl Mingw              windows                    N      OK
 dnl
-dnl BeOS 5            --
+dnl BeOS 5             --
 dnl
 dnl The test-lock result shows what happens if in test-lock.c EXPLICIT_YIELD is
 dnl turned off: