title: Warning while building project using Qt 5.1 on OSX
body: <p>I am getting two warnings while trying to build Qt projects on Mac (using QtCreator).</p>
  
  <blockquote>
    <p>warning: No .qmake.cache is present. This significantly slows down
    qmake with this makespec. warning: Call 'cache()' in the top-level
    project file to rectify this problem.</p>
  </blockquote>
  
  <p>The warning instructs to call <code>cache()</code> in the top level project, but I don't find any documentation on how I should do that.</p>
  
  <p>I see some bugs logged on qt</p>
  
  <ol>
  <li><a href="https://bugreports.qt.io/browse/QTBUG-31340" rel="nofollow noreferrer">https://bugreports.qt.io/browse/QTBUG-31340</a></li>
  <li><a href="https://bugreports.qt.io/browse/QTBUG-30586" rel="nofollow noreferrer">https://bugreports.qt.io/browse/QTBUG-30586</a></li>
  </ol>
  
  <p>I know this is just a warning, but I am interested in fixing it. Is there any workaround to fix it?</p>