caskroom/homebrew-cask — pull request #8539 by rolandwalker (2014-12-30 16:31:57+00:00)
Title: incorporate a modified homebrew-fork `OS::Mac` into our codebase as `Cask::MacOS`

temporarily define `::MacOS = Cask::MacOS` pending updates to the DSL (it should be visible at the top level only within Casks.)