I\'m getting the following when running \"$ bundle\" after adding \"gem \'redcarpet\'\" to Gemfile:
$ bundle ... Using paperclip (2.3.11) Using passenger (3.0.7
If you have Mountain Lion and XCODE 4.4.1 you have to go here https://developer.apple.com/downloads/index.action and download the command line tool (it's free so you don't have to pay for iOS or MAC developer program) to download this tool.
It works for me.