title: Does Qt offer a (guaranteed) debug definition?
body: <p>Does anyone know an officially supported way to include debug-build only code in Qt? For example:</p>
  
  <pre><code>#ifdef QT_DEBUG
  // do something
  #endif
  </code></pre>
  
  <p>Basically like Q_ASSERT but for more complex tests.</p>
  
  <p>I can't seem to find any documentation which says that the Qt framework guarantees to define a debug macro. If there isn't, what would be a sensible <em>unofficial</em> way to implement this feature project wide?</p>