title: qmake: could not find a Qt installation of ''
body: <p>I have a software in ubuntu that requires me to run qmake  to generate the Makefile.</p>
  
  <p>However, running qmake gives back this error,</p>
  
  <pre><code>qmake: could not find a Qt installation of ''
  </code></pre>
  
  <p>I have installed what I thought to be the required packages using,</p>
  
  <pre><code>sudo apt-get install qt4-qmake
  sudo apt-get install qt5-qmake
  </code></pre>
  
  <p>But the error didn't go away.</p>
  
  <p>Any help on this would be gladly appreciated!</p>