(this is what r25545 should have been)

Per http://www.open-mpi.org/community/lists/users/2011/11/17862.php,
to make MPI_IN_PLACE (and other sentinel Fortran constants) work on OS
X, we need to use the following compiler (linker) flag:

    -Wl,-commons,use_dylibs 

So if we're compiling on OS X, test to see if that flag works with the
compiler. If so, add it to the wrapper FFLAGS and FCFLAGS (note that
per a future update, we'll only have one Fortran compiler anyway).

Fixes trac:1982. 

This commit was SVN r25547.

The following SVN revision numbers were found above:
  r25545 --> open-mpi/ompi@7f9ae11faf

The following Trac tickets were found above:
  Ticket 1982 --> https://svn.open-mpi.org/trac/ompi/ticket/1982

ompi/config/ompi_setup_f77.m4

@@ -143,6 +143,37 @@ else
     AC_LANG_POP
 fi
 
+# Per #1982, on OS X, we may need some esoteric linker flags in the
+# wrapper compilers.  Assume that we need it for both F77 and FC flags
+# (note that in an upcoming update where there will only be one
+# Fortran compiler, anyway).
+AC_MSG_CHECKING([to see if mpif77/mpif90 compilers need additional linker flags])
+if test $OMPI_WANT_F77_BINDINGS -eq 0; then
+    AC_MSG_RESULT([none (no F77 bindings)])
+else
+    case "$host" in
+    *apple-darwin*)
+        # Test whether -Wl,-commons,use_dylibs works; if it does, use it.
+        LDFLAGS_save=$LDFLAGS
+        LDFLAGS="$LDFLAGS -Wl,-commons,use_dylibs"
+        AC_LANG_PUSH(Fortran 77)
+        AC_LINK_IFELSE([AC_LANG_SOURCE([[       program test
+        integer :: i
+        end program]])],
+                       [OMPI_FORTRAN_WRAPPER_FLAGS="-Wl,-commons,use_dylibs"
+                        WRAPPER_EXTRA_FFLAGS="$WRAPPER_EXTRA_FFLAGS $OMPI_FORTRAN_WRAPPER_FLAGS"
+                        WRAPPER_EXTRA_FCFLAGS="$WRAPPER_EXTRA_FCFLAGS $OMPI_FORTRAN_WRAPPER_FLAGS"],
+                       [OMPI_FORTRAN_WRAPPER_FLAGS=none])
+        AC_LANG_POP
+        LDFLAGS=$LDFLAGS_save
+        AC_MSG_RESULT([$OMPI_FORTRAN_WRAPPER_FLAGS])
+        ;;
+    *)
+        AC_MSG_RESULT([none])
+        ;;
+    esac
+fi
+
 AC_DEFINE_UNQUOTED(OMPI_WANT_F77_BINDINGS, $OMPI_WANT_F77_BINDINGS,
     [Whether we want the MPI f77 bindings or not])
 AC_DEFINE_UNQUOTED(OMPI_F77, "$OMPI_F77", [OMPI underlying F77 compiler])