title: <QtWidgets> file not found after brew install qt5
body: <p>I have recently just installed qt5 through the command 'brew install qt5' on my terminal, but when I try run a programme I get this error: </p>
  
  <pre><code>In file included from albums.cpp:4:
  ./albums.hpp:6:10: fatal error: 'QtWidgets' file not found
  #include &lt;QtWidgets&gt;
       ^
  1 error generated.
  make: *** [albums.o] Error 1
  </code></pre>
  
  <p>Any recommendations? And yes I have looked through answers from people which have had the same problem but none of them help.</p>
  
  <p>Many Thanks</p>