title: How can I add an #ifdef DEBUG to Xcode?
body: <p>I have some code in a project which should never be used in the release build, but is useful when testing. I'd like to do something like this:</p>
  
  <pre><code>#ifdef DEBUG
      // Run my debugging only code
  #endif
  </code></pre>
  
  <p>Where do I add the DEBUG setting in Xcode 4? I tried putting it in the "Edit Scheme" under Run MyApp->Arguments Passed On Launch, but it didn't work. Alternatively, is there a flag already available for this?</p>