Update gcc from 4.6.0 to 4.6.4

Commit on top of master with arch-specific patches would build, however strawberry-dev would not. May need a test build on a non-arch computer to verify nothing breaks.

Travis will probably mark this as ok because it doesn't compile the toolchain. (EDIT: actually, seems like travis is already broken for the strawberry-dev branch, so it will probably fail this change as well)