title: Use extern "C" in Swift?
body: <p>I wondered, is there an alternative to <code>extern "C"</code> in Swift?
  I want to write a simple Unity plugin, and as an Obj-C noob I'd like to do it in Swift if possible.
  Right now I have a very basic Obj-C code to show UIAlertView using </p>
  
  <pre><code>extern "C" 
  { 
      void _addAlert() 
      //Whatever
  } 
  </code></pre>
  
  <p>And in Unity it's hooked up with </p>
  
  <pre><code>private static extern void _addAlert()
  {
      //Same whatever
  } 
  </code></pre>
  
  <p>I'm looking for a way to use Swift instead of Obj-C.
  Is that possible?</p>