Fix a few problems with the compiler visibility test:

* Update to be safe for AC 2.68 by using AC_LINK_IFELSE instead of
   AC_TRY_LINK
 * If enable visibility was used, ensure we fail if the compiler
   doesn't support it
 * Rename OMPI_CHECK_VISIBILITY -> OPAL_CHECK_VISIBILITY (and all
   internal variables)

This commit was SVN r23923.

configure.ac

@@ -1009,7 +1009,7 @@ AC_CACHE_SAVE
 # the visibility feature.
 ompi_show_title "Symbol visibility feature"
 
-OMPI_CHECK_VISIBILITY
+OPAL_CHECK_VISIBILITY
 
 
 

opal/config/opal_check_visibility.m4

@@ -10,7 +10,7 @@
 #                         University of Stuttgart.  All rights reserved.
 # Copyright (c) 2004-2005 The Regents of the University of California.
 #                         All rights reserved.
-# Copyright (c) 2006-2007 Cisco Systems, Inc.  All rights reserved.
+# Copyright (c) 2006-2010 Cisco Systems, Inc.  All rights reserved.
 # Copyright (c) 2009      Sun Microsystems, Inc.  All rights reserved.
 # $COPYRIGHT$
 # 
@@ -19,19 +19,18 @@
 # $HEADER$
 #
 
-
+# OPAL_CHECK_VISIBILITY
-# OMPI_CHECK_VISIBILITY
 # --------------------------------------------------------
-AC_DEFUN([OMPI_CHECK_VISIBILITY],[
+AC_DEFUN([OPAL_CHECK_VISIBILITY],[
     AC_REQUIRE([AC_PROG_GREP])
 
     # Check if the compiler has support for visibility, like some versions of gcc, icc Sun Studio cc.
     AC_ARG_ENABLE(visibility, 
         AC_HELP_STRING([--enable-visibility],
             [enable visibility feature of certain compilers/linkers (default: enabled)]))
-    if test "$enable_visibility" = "no" -o "$opal_cv___attribute__visibility" = "0"; then
+    if test "$enable_visibility" = "no"; then
-        AC_MSG_CHECKING([enable symbol visibility])
+        AC_MSG_CHECKING([whether to enable symbol visibility])
-        AC_MSG_RESULT([no]) 
+        AC_MSG_RESULT([no (disabled)]) 
         have_visibility=0
     else
         CFLAGS_orig="$CFLAGS"
@@ -40,71 +39,69 @@ AC_DEFUN([OMPI_CHECK_VISIBILITY],[
         # check using gcc -fvisibility=hidden flag
         CFLAGS="$CFLAGS_orig -fvisibility=hidden"
         AC_CACHE_CHECK([if $CC supports -fvisibility],
-            [ompi_cv_cc_fvisibility],
+            [opal_cv_cc_fvisibility],
-            [AC_TRY_LINK([
+            [AC_LINK_IFELSE([AC_LANG_PROGRAM([[
-                    #include <stdio.h>
                     __attribute__((visibility("default"))) int foo;
-                    void bar(void) { fprintf(stderr, "bar\n"); }
+                    ]],[[int i;]])],
-                    ],[],
+                    [opal_cv_cc_fvisibility=yes],
                     [if test -s conftest.err ; then
                         $GREP -iq "visibility" conftest.err
                         if test "$?" = "0" ; then
-                            ompi_cv_cc_fvisibility="no"
+                            opal_cv_cc_fvisibility=no
                         else
-                            ompi_cv_cc_fvisibility="yes"
+                            opal_cv_cc_fvisibility=yes
                         fi
                      else
-                        ompi_cv_cc_fvisibility="yes"
+                        opal_cv_cc_fvisibility=yes
                      fi],
-                    [ompi_cv_cc_fvisibility="no"])
+                    [opal_cv_cc_fvisibility=no])
                 ])
         if test "$ompi_c_vendor" = "sun" ; then
             # Check using Sun Studio -xldscope=hidden flag
             CFLAGS="$CFLAGS_orig -xldscope=hidden"
             AC_CACHE_CHECK([if $CC supports -xldscope],
-                [ompi_cv_cc_xldscope],
+                [opal_cv_cc_xldscope],
-                [AC_TRY_LINK([
+                [AC_LINK_IFELSE([AC_LANG_PROGRAM([[
-                        #include <stdio.h>
                         __attribute__((visibility("default"))) int foo;
-                        void bar(void) { fprintf(stderr, "bar\n"); }
+                        ]],[[int i;]])],
-                        ],[],
+                        [opal_cv_cc_fvisibilty=yes],
                         [if test -s conftest.err ; then
                             $GREP -iq "visibility" conftest.err
                             if test "$?" = "0" ; then
-                                ompi_cv_cc_xldscope="no"
+                                opal_cv_cc_xldscope="no"
                             else
-                                ompi_cv_cc_xldscope="yes"
+                                opal_cv_cc_xldscope="yes"
                             fi
                          else
-                            ompi_cv_cc_xldscope="yes"
+                            opal_cv_cc_xldscope="yes"
                          fi],
-                        [ompi_cv_cc_xldscope="no"])
+                        [opal_cv_cc_xldscope="no"])
                     ])
         fi 
-        if test "$ompi_cv_cc_fvisibility" = "yes" ; then
+        if test "$opal_cv_cc_fvisibility" = "yes" ; then
             add=" -fvisibility=hidden"
             have_visibility=1
-            AC_MSG_CHECKING([enable symbol visibility])
+            AC_MSG_CHECKING([whether to enable symbol visibility])
-            AC_MSG_RESULT([yes]) 
+            AC_MSG_RESULT([yes (via$add)]) 
             AC_MSG_WARN([$add has been added to CFLAGS])
-        elif test "$ompi_cv_cc_xldscope" = "yes" ; then
+        elif test "$opal_cv_cc_xldscope" = "yes" ; then
             add=" -xldscope=hidden"
             have_visibility=1
-            AC_MSG_CHECKING([enable symbol visibility])
+            AC_MSG_CHECKING([whether to enable symbol visibility])
-            AC_MSG_RESULT([yes]) 
+            AC_MSG_RESULT([yes (via$add)]) 
             AC_MSG_WARN([$add has been added to CFLAGS])
         elif test "$enable_visibility" = "yes"; then
             AC_MSG_ERROR([Symbol visibility support requested but compiler does not seem to support it.  Aborting])
         else 
-            AC_MSG_CHECKING([enable symbol visibility])
+            AC_MSG_CHECKING([whether enable symbol visibility])
-            AC_MSG_RESULT([no]) 
+            AC_MSG_RESULT([no (unsupported)]) 
             have_visibility=0
         fi
         CFLAGS="$CFLAGS_orig$add"
         OPAL_VISIBILITY_CFLAGS="$add"
         unset add 
     fi
+
     AC_DEFINE_UNQUOTED([OPAL_C_HAVE_VISIBILITY], [$have_visibility],
             [Whether C compiler supports -fvisibility])
-
 ])