Pass MOZ_TOPSRCDIR to altoptions.m4. This allows third parties (like netscape)...

Pass MOZ_TOPSRCDIR to altoptions.m4. This allows third parties (like netscape) to refer to the mozilla copy rather than copying it (and mozconfig2configure and mozconfig-find) into their own tree.

aclocal.m4

@@ -6,5 +6,7 @@ dnl
 builtin(include, build/autoconf/glib.m4)dnl
 builtin(include, build/autoconf/gtk.m4)dnl
 builtin(include, build/autoconf/libIDL.m4)dnl
+dnl
+define(MOZ_TOPSRCDIR,.)dnl MOZ_TOPSRCDIR is used in altoptions.m4
 builtin(include, build/autoconf/altoptions.m4)dnl