title: How to get 10.8 SDK and 5.1 compiler in Xcode 6
body: <p>as from the title, I need to use the 10.8 SDK and the 5.1 (or 5.0) LLVM compiler with Xcode 6, in Mavericks.
  With the previous Xcode, it was possible to have both the SDKs, but now I see only the 10.9 one.
  How can I install the previous SDK and  compiler in Xcode 6?</p>