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Update acx_pthread to the latest version we use internally. This is

like the one on the cryp.to autoconf repository website, but with the
avahi patches added in to deal with some compiler quirks.  However,
these patches have been rewritten internally within google to make
them more robust.  In particular, the new code now works with cygwin,
which it previously didn't (resulting in the spurious error: "Unable
to determine how to use pthreads with shared libraries").

Tested by running configure on cygwin.

Reviewed by klarlund@google.com and fergus@google.com
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1 parent d240f01 commit b314c856b5b1ab5d5803b48f48d962efd87eca28 @csilvers csilvers committed May 14, 2008
Showing with 114 additions and 104 deletions.
  1. +114 −104 m4/acx_pthread.m4
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@@ -1,7 +1,12 @@
# This was retrieved from
-# http://0pointer.de/cgi-bin/viewcvs.cgi/trunk/common/acx_pthread.m4?rev=1227
+# http://svn.0pointer.de/viewvc/trunk/common/acx_pthread.m4?revision=1277&root=avahi
# See also (perhaps for new versions?)
-# http://0pointer.de/cgi-bin/viewcvs.cgi/trunk/common/acx_pthread.m4
+# http://svn.0pointer.de/viewvc/trunk/common/acx_pthread.m4?root=avahi
+#
+# We've rewritten the inconsistency check code (from avahi), to work
+# more broadly. In particular, it no longer assumes ld accepts -zdefs.
+# This caused a restructing of the code, but the functionality has only
+# changed a little.
dnl @synopsis ACX_PTHREAD([ACTION-IF-FOUND[, ACTION-IF-NOT-FOUND]])
dnl
@@ -231,108 +236,113 @@ if test "x$acx_pthread_ok" = xyes; then
PTHREAD_CC=$CC
fi
- # The next part tries to detect GCC inconsistency with -shared on some
- # architectures and systems. The problem is that in certain
- # configurations, when -shared is specified, GCC "forgets" to
- # internally use various flags which are still necessary.
-
- AC_MSG_CHECKING([whether to check for GCC pthread/shared inconsistencies])
- check_inconsistencies=yes
- case "${host_cpu}-${host_os}" in
- *-darwin*) check_inconsistencies=no ;;
- esac
- if test x"$GCC" != xyes -o "x$check_inconsistencies" != xyes ; then
- AC_MSG_RESULT([no])
- else
- AC_MSG_RESULT([yes])
-
- # In order not to create several levels of indentation, we test
- # the value of "$ok" until we find out the cure or run out of
- # ideas.
- ok="no"
-
- #
- # Prepare the flags
- #
- save_CFLAGS="$CFLAGS"
- save_LIBS="$LIBS"
- save_CC="$CC"
- # Try with the flags determined by the earlier checks.
- #
- # -Wl,-z,defs forces link-time symbol resolution, so that the
- # linking checks with -shared actually have any value
- #
- # FIXME: -fPIC is required for -shared on many architectures,
- # so we specify it here, but the right way would probably be to
- # properly detect whether it is actually required.
- CFLAGS="-shared -fPIC -Wl,-z,defs $CFLAGS $PTHREAD_CFLAGS"
- LIBS="$PTHREAD_LIBS $LIBS"
- CC="$PTHREAD_CC"
-
- AC_MSG_CHECKING([whether -pthread is sufficient with -shared])
- AC_TRY_LINK([#include <pthread.h>],
- [pthread_t th; pthread_join(th, 0);
- pthread_attr_init(0); pthread_cleanup_push(0, 0);
- pthread_create(0,0,0,0); pthread_cleanup_pop(0); ],
- [ok=yes])
-
- if test "x$ok" = xyes; then
- AC_MSG_RESULT([yes])
- else
- AC_MSG_RESULT([no])
- fi
-
- #
- # Linux gcc on some architectures such as mips/mipsel forgets
- # about -lpthread
- #
- if test x"$ok" = xno; then
- AC_MSG_CHECKING([whether -lpthread fixes that])
- LIBS="-lpthread $PTHREAD_LIBS $save_LIBS"
- AC_TRY_LINK([#include <pthread.h>],
- [pthread_t th; pthread_join(th, 0);
- pthread_attr_init(0); pthread_cleanup_push(0, 0);
- pthread_create(0,0,0,0); pthread_cleanup_pop(0); ],
- [ok=yes])
-
- if test "x$ok" = xyes; then
- AC_MSG_RESULT([yes])
- PTHREAD_LIBS="-lpthread $PTHREAD_LIBS"
- else
- AC_MSG_RESULT([no])
- fi
- fi
- #
- # FreeBSD 4.10 gcc forgets to use -lc_r instead of -lc
- #
- if test x"$ok" = xno; then
- AC_MSG_CHECKING([whether -lc_r fixes that])
- LIBS="-lc_r $PTHREAD_LIBS $save_LIBS"
- AC_TRY_LINK([#include <pthread.h>],
- [pthread_t th; pthread_join(th, 0);
- pthread_attr_init(0); pthread_cleanup_push(0, 0);
- pthread_create(0,0,0,0); pthread_cleanup_pop(0); ],
- [ok=yes])
-
- if test "x$ok" = xyes; then
- AC_MSG_RESULT([yes])
- PTHREAD_LIBS="-lc_r $PTHREAD_LIBS"
- else
- AC_MSG_RESULT([no])
- fi
- fi
- if test x"$ok" = xno; then
- # OK, we have run out of ideas
- AC_MSG_WARN([Impossible to determine how to use pthreads with shared libraries])
-
- # so it's not safe to assume that we may use pthreads
- acx_pthread_ok=no
- fi
-
- CFLAGS="$save_CFLAGS"
- LIBS="$save_LIBS"
- CC="$save_CC"
- fi
+ # The next part tries to detect GCC inconsistency with -shared on some
+ # architectures and systems. The problem is that in certain
+ # configurations, when -shared is specified, GCC "forgets" to
+ # internally use various flags which are still necessary.
+
+ #
+ # Prepare the flags
+ #
+ save_CFLAGS="$CFLAGS"
+ save_LIBS="$LIBS"
+ save_CC="$CC"
+
+ # Try with the flags determined by the earlier checks.
+ #
+ # -Wl,-z,defs forces link-time symbol resolution, so that the
+ # linking checks with -shared actually have any value
+ #
+ # FIXME: -fPIC is required for -shared on many architectures,
+ # so we specify it here, but the right way would probably be to
+ # properly detect whether it is actually required.
+ CFLAGS="-shared -fPIC -Wl,-z,defs $CFLAGS $PTHREAD_CFLAGS"
+ LIBS="$PTHREAD_LIBS $LIBS"
+ CC="$PTHREAD_CC"
+
+ # In order not to create several levels of indentation, we test
+ # the value of "$done" until we find the cure or run out of ideas.
+ done="no"
+
+ # First, make sure the CFLAGS we added are actually accepted by our
+ # compiler. If not (and OS X's ld, for instance, does not accept -z),
+ # then we can't do this test.
+ if test x"$done" = xno; then
+ AC_MSG_CHECKING([whether to check for GCC pthread/shared inconsistencies])
+ AC_TRY_LINK(,, , [done=yes])
+
+ if test "x$done" = xyes ; then
+ AC_MSG_RESULT([no])
+ else
+ AC_MSG_RESULT([yes])
+ fi
+ fi
+
+ if test x"$done" = xno; then
+ AC_MSG_CHECKING([whether -pthread is sufficient with -shared])
+ AC_TRY_LINK([#include <pthread.h>],
+ [pthread_t th; pthread_join(th, 0);
+ pthread_attr_init(0); pthread_cleanup_push(0, 0);
+ pthread_create(0,0,0,0); pthread_cleanup_pop(0); ],
+ [done=yes])
+
+ if test "x$done" = xyes; then
+ AC_MSG_RESULT([yes])
+ else
+ AC_MSG_RESULT([no])
+ fi
+ fi
+
+ #
+ # Linux gcc on some architectures such as mips/mipsel forgets
+ # about -lpthread
+ #
+ if test x"$done" = xno; then
+ AC_MSG_CHECKING([whether -lpthread fixes that])
+ LIBS="-lpthread $PTHREAD_LIBS $save_LIBS"
+ AC_TRY_LINK([#include <pthread.h>],
+ [pthread_t th; pthread_join(th, 0);
+ pthread_attr_init(0); pthread_cleanup_push(0, 0);
+ pthread_create(0,0,0,0); pthread_cleanup_pop(0); ],
+ [done=yes])
+
+ if test "x$done" = xyes; then
+ AC_MSG_RESULT([yes])
+ PTHREAD_LIBS="-lpthread $PTHREAD_LIBS"
+ else
+ AC_MSG_RESULT([no])
+ fi
+ fi
+ #
+ # FreeBSD 4.10 gcc forgets to use -lc_r instead of -lc
+ #
+ if test x"$done" = xno; then
+ AC_MSG_CHECKING([whether -lc_r fixes that])
+ LIBS="-lc_r $PTHREAD_LIBS $save_LIBS"
+ AC_TRY_LINK([#include <pthread.h>],
+ [pthread_t th; pthread_join(th, 0);
+ pthread_attr_init(0); pthread_cleanup_push(0, 0);
+ pthread_create(0,0,0,0); pthread_cleanup_pop(0); ],
+ [done=yes])
+
+ if test "x$done" = xyes; then
+ AC_MSG_RESULT([yes])
+ PTHREAD_LIBS="-lc_r $PTHREAD_LIBS"
+ else
+ AC_MSG_RESULT([no])
+ fi
+ fi
+ if test x"$done" = xno; then
+ # OK, we have run out of ideas
+ AC_MSG_WARN([Impossible to determine how to use pthreads with shared libraries])
+
+ # so it's not safe to assume that we may use pthreads
+ acx_pthread_ok=no
+ fi
+
+ CFLAGS="$save_CFLAGS"
+ LIBS="$save_LIBS"
+ CC="$save_CC"
else
PTHREAD_CC="$CC"
fi

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