title: Xcode does not autocomplete for OSX code
body: <p>It is OK for Xcode autocompletion when I write iOS codes. But if I wrote something like</p>
  
  <pre><code>#if os(OSX)
      return [
          NSApplicationWillResignActiveNotification,
          NSWindowDidMiniaturizeNotification
      ]
  </code></pre>
  
  <p>Xcode would not autocomplete the constant from AppKit, and there is no syntax color either. Please help.</p>