Patch libtool.m4 after every autoreconf and fix timestamp.

Fixes ticket #1870.
Signed-off-by: Pavan Balaji <balaji@mcs.anl.gov>

autogen.sh

@@ -903,28 +903,26 @@ if [ "$do_build_configure" = "yes" ] ; then
 	    echo "------------------------------------------------------------------------"
 	    echo "running $autoreconf in $amdir"
             (cd $amdir && $autoreconf $autoreconf_args) || exit 1
-	fi
-    done
-fi
-
-########################################################################
-## Patching libtool.m4
-########################################################################
-
-# This works with libtool versions 2.4 - 2.4.2.
-# Older versions are not supported to build mpich.
-# Newer versions should have this patch already included.
-# There is no need to patch if we're not going to use Fortran.
-if [ $do_bindings = "yes" ] ; then
-    echo "------------------------------------------------------------------------"
-    echo
+            # Patching libtool.m4
+            # This works with libtool versions 2.4 - 2.4.2.
+            # Older versions are not supported to build mpich.
+            # Newer versions should have this patch already included.
+            # There is no need to patch if we're not going to use Fortran.
+            if [ $do_bindings = "yes" ] ; then
+                if [ -f $amdir/confdb/libtool.m4 ] ; then
                     echo_n "Patching libtool.m4 for compatibility with nagfor shared libraries... "
-    patch --forward -p0 -s -l < maint/libtool.m4.patch
-    rm -f confdb/libtool.m4.orig
+                    patch --forward -s -l $amdir/confdb/libtool.m4 maint/libtool.m4.patch
                     if [ $? -eq 0 ] ; then
                         echo "done"
+                        # Remove possible leftovers, which don't imply a failure
+                        rm -f $amdir/confdb/libtool.m4.orig
+                        # Reset libtool.m4 timestamps to avoid confusing make
+                        touch $amdir/confdb/libtool.m4 -r $amdir/confdb/ltversion.m4
                     else
                         echo "failed"
-        exit 1
                     fi
+                fi
+            fi
+	fi
+    done
 fi