title: Compiling GCDAsyncSocket for OS X 10.6
body: <p>I have troubles with compiling this wonderful TCP library with SDK 10.6.</p>
  
  <p>I get:</p>
  
  <pre><code>/Users/cisary/Desktop/AI/AI/TCP/GCDAsyncSocket.m:185:11: error: instance variables may not be placed in class extension
          uint32_t flags;
                   ^
  /Users/cisary/Desktop/AI/AI/TCP/GCDAsyncSocket.m:186:11: error: instance variables may not be placed in class extension
          uint16_t config;
  </code></pre>
  
  <p>What does <code>instance variables may not be placed in class extension</code> mean?</p>