title: ExtJS - sencha app build dependency error
body: <p>I'm trying to extend a third party class. The code is something like this. Note I'm specifying where to load <code>openGL.view</code>.</p>
  
  <pre><code>Ext.Loader.setPath({
      'openGL.view': 'C:/Users/«username»/Documents/third-party/openGL/view/'
  });
  
  Ext.define('myOpenGL.view.Qxga',{
      extend: 'openGL.view.Uxga',
      alias: 'widget.qxga',
      itemId: 'qxga',
      requires: [
              'openGL.view.Uxga',
              'myOpenGL.view.QxgaController'
      ],
      controller: 'QxgaController'
  });
  </code></pre>
  
  <p>When I build it, I get errors like this:</p>
  
  <pre><code>[ERR] Failed to resolve dependency openGL.view.Uxga for file myOpenGL.view.Qxga
  [ERR]
  [ERR] BUILD FAILED
  [ERR] com.sencha.exceptions.ExNotFound: Unknown definition for dependency : openGL.view.Uxga
  [ERR]
  [ERR] Total time: 6 seconds
  [ERR] The following error occurred while executing this line:
  C:\Users\«username»\Applications\Sencha\Cmd\5.1.0.26\plugins\ext\current\plugin.xml:403: The following error occurred while executing this line:
  C:\Users\«username»\Documents\workspace\openGL\.sencha\app\build-impl.xml:378: The following error occurred while executing this line:
  C:\Users\«username»\Documents\workspace\openGL\.sencha\app\init-impl.xml:303: com.sencha.exceptions.ExNotFound: Unknown definition for dependency : openGL.view.Uxga
  </code></pre>
  
  <p>Some questions:</p>
  
  <ul>
  <li>Why isn't it finding <code>openGL.view.Uxga</code>?</li>
  <li>I've read about modifying <code>build-impl.xml</code>, but with various degrees of success. What would I have to do, and is there a way to do the same without having to modify the file? Say some kind of override or command line parameter?</li>
  <li>If there is a way to do this using <code>setPath</code>, the <code>third-party</code> directory may not be in the same place. Is there a way to include a Windows environment variable or something similar?</li>
  </ul>