Set LDFLAGS when changing build_arch.
Set LDFLAGS when changing build_arch.

git-svn-id: 620571fa9b4bd0cbce9a0cf901e91ef896adbf27@60662 d073be05-634f-4543-b044-5fe20cf6d1d6

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