title: How to add specific flags to moc in a qmake project?
body: <p>I compile a Qt executable using <code>qmake &amp;&amp; make</code> on the following <code>project.pro</code> file:</p>
  
  <pre><code>INCLUDEPATH *= ../../dependencies/boost
  QT *= opengl xml
  CONFIG *= qt opengl static
  
  TARGET = myexe
  HEADERS = Viewer.hpp MainWindow.hpp Inspector.hpp
  SOURCES = main.cpp Viewer.cpp MainWindow.cpp Inspector.cpp
  </code></pre>
  
  <p>However, when compiling, <code>moc</code> chokes on a boost macro which it cannot parse. To work around <a href="https://bugreports.qt.nokia.com/browse/QTBUG-22829">this bug</a>, I need to pass the flag <code>-DBOOST_TT_HAS_OPERATOR_HPP_INCLUDED</code> to moc, but I cannot manage to do so.</p>
  
  <p>How to I edit my <code>.pro</code> file to pass a given flag to <code>moc</code>? (but not to <code>g++</code>, as <code>QMAKE_CXXFLAGS</code> does)</p>