[Config] Make GCC symbol exporting work on GCC 4.0, where symbol hiding already worked.  Yes, this unbreaks things.
[Config] Make GCC symbol exporting work on GCC 4.0, where symbol hiding already worked.  Yes, this unbreaks things.

git-svn-id: 6e74a02f85675cec270f5d931b0f6998666294a3@18807 d31e2699-5ff4-0310-a27c-f18f2fbe73fe

ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot,ashgti/parrot