This regards Issue Homebrew/homebrew#30.
Turns out -march=native isn't supported by Apple's GCC, but while investigating it I found they'd back ported the -march=core2 option, so we win anyway.
Logic reverted to how it was yesterday.
I moved the gcc options stuff back to brewkit.rb as we manipulate the cflags more later and it seemed bad form to split the logic for this area over two files.
Additionally the brew command exits immediately on powerpc now. Brewkit doesn't throw as theoretically it is a useful library file for other projects.
Simplified hardware model testing.
Even smarter compiler option generation using sysctl and new GCC 4.2 features.
Get processor count from sysctl and thus remove our dependency on RubyCocoa.
