brewkit.rb changes ENV destructively, so lets not do that everytime a formula is required. Now it's possible for other tools to require a formula description without worrying about side-effects.
Because OS X provides it and you shouldn't be linking against our version unintentionally.
Signed-off-by: Adam Vandenberg Cleaned up formula. Signed-off-by: Max Howell <max@methylblue.com> Fixes Homebrew/homebrew#89