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|
http://bugs.gentoo.org/247067
--- m4/ax_pthread.m4
+++ m4/ax_pthread.m4
@@ -266,6 +266,117 @@
else
PTHREAD_CC=$CC
fi
+
+ # The next part tries to detect GCC inconsistency with -shared on some
+ # architectures and systems. The problem is that in certain
+ # configurations, when -shared is specified, GCC "forgets" to
+ # internally use various flags which are still necessary.
+
+ #
+ # Prepare the flags
+ #
+ save_LDFLAGS="$LDFLAGS"
+ 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" = xyes; then
+ done="no"
+ 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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