title: Compile time error from a Qt file: expected unqualified-id before ')' token
body: <p>Porting my project from Qt4 to Qt5.1, I get this error from a Qt file:</p>
  
  <pre><code>C:\Qt\Qt5.1.1\5.1.1\mingw48_32\include\QtGui\qopenglversionfunctions.h:785: error: expected unqualified-id before ')' token
       void (QOPENGLF_APIENTRYP MemoryBarrier)(GLbitfield barriers);
                                             ^
  </code></pre>
  
  <p>This is the chain of defines:</p>
  
  <pre><code>#define QOPENGLF_APIENTRYP QOPENGLF_APIENTRY *
  #define QOPENGLF_APIENTRY APIENTRY
  #define APIENTRY WINAPI
  #define WINAPI __stdcall
  </code></pre>
  
  <p>I noticed that the "MemoryBarrier" token is present in the libQt5OpenGLExtensionsd.a library. Should I include it, even if in the original Qt4 project nothing related to OpenGL was used?</p>
  
  <p>Platform:<br>
  Windows 7<br>
  MinGW 4.8<br>
  Qt 4.8 --> Qt 5.1  </p>