base: Remove objc/objc-api.h from GNU Obj-C runtime configure check, since that causes configure to fail on Linux with GCC >= 4.7
base: Remove objc/objc-api.h from GNU Obj-C runtime configure check, since that causes configure to fail on Linux with GCC >= 4.7

See http://gcc.gnu.org/onlinedocs/gcc/Traditional-GNU-Objective-C-runtime-API.html.

git-svn-id: 620571fa9b4bd0cbce9a0cf901e91ef896adbf27@119987 d073be05-634f-4543-b044-5fe20cf6d1d6

danchr/macports-base,neverpanic/macports-base,danchr/macports-base,macports/macports-base,macports/macports-base,neverpanic/macports-base