Massive commit squash encompassing all commits needed to:

* Get bottles building on 10.8 but running on 10.6
* Relocate .pc files intelligently
* Fix Homebrew tabs so we can detect in post_install when we've been poured from a bottle
* Do more aggressive binary file relocation
Remove MACOS
No more xz. :(
Tweak regex
Merge branch 'kegpkg' of github.com:staticfloat/homebrew into kegpkg

Conflicts:
	Library/Homebrew/cmd/bottle.rb
	Library/Homebrew/keg_fix_install_names.rb