Make C compiler flags more portable.
Make C compiler flags more portable.

Fix extra cflags so that we start off with what's in RbConfig::CONFIG rather
than a specific set of GCC flags.

git-svn-id: 0e6074679e66e8f1cc73dfc755b08bab367f805b@1302025 13f79535-47bb-0310-9956-ffa450edef68

nwellnhof/lucy-clownfish,apache/lucy-clownfish,nwellnhof/lucy-clownfish,apache/lucy-clownfish,apache/lucy-clownfish,apache/lucy-clownfish,nwellnhof/lucy-clownfish,apache/lucy-clownfish,rectang/lucy-clownfish,nwellnhof/lucy-clownfish,nwellnhof/lucy-clownfish,nwellnhof/lucy-clownfish,apache/lucy-clownfish,rectang/lucy-clownfish,apache/lucy-clownfish,rectang/lucy-clownfish,rectang/lucy-clownfish,rectang/lucy-clownfish,rectang/lucy-clownfish,rectang/lucy-clownfish,rectang/lucy-clownfish,nwellnhof/lucy-clownfish,nwellnhof/lucy-clownfish,rectang/lucy-clownfish,apache/lucy-clownfish