x86_64: support PIC and therefore, Mac OS X in the NCG
Supporting x86_64-apple-darwin in the NCG basically boils down to supporting position-independent code in the NCG. PIC code works almost exactly the same as on x86_64-linux, while position-dependent code is not supported at all. This patch implements -fPIC for x86_64-linux, too, but that is untested.
Showing with 199 additions and 108 deletions