Pass visibility flags to libltdl's CFLAGS, which will result in libltdl

being hidden in libopal.  This seems to make applications which also
use libltdl play nicer.

This commit was SVN r21731.

NEWS

@@ -47,6 +47,10 @@ Trunk (not on release branches yet)
 1.3.4 (expected)
 ----------------
 
+- Pass visibility flags to libltdl's configure script, resulting in
+  those symbols being hidden.  This appears to mainly solve the
+  problem of applications attempting to use different versions of
+  libltdl from that used to build Open MPI.
 
 
 1.3.3

config/opal_check_visibility.m4

@@ -101,6 +101,7 @@ AC_DEFUN([OMPI_CHECK_VISIBILITY],[
             have_visibility=0
         fi
         CFLAGS="$CFLAGS_orig$add"
+        OPAL_VISIBILITY_CFLAGS="$add"
         unset add 
     fi
     AC_DEFINE_UNQUOTED([OPAL_C_HAVE_VISIBILITY], [$have_visibility],

configure.ac

@@ -1231,7 +1231,7 @@ if test "$OPAL_ENABLE_DLOPEN_SUPPORT" = "1" ; then
     fi
 
     CFLAGS_save="$CFLAGS"
-    CFLAGS="$OMPI_CFLAGS_BEFORE_PICKY"
+    CFLAGS="$OMPI_CFLAGS_BEFORE_PICKY $OPAL_VISIBILITY_CFLAGS"
 
     OMPI_CONFIG_SUBDIR(opal/libltdl, [$ompi_subdir_args], [HAPPY=1], [HAPPY=0])
     if test "$HAPPY" = "1"; then