title: Unable to build qt module qtx11extras
body: <p>The system configuration is as below,
  OS - RHEL 6
  QT - Qt5.5.0
  Platform - X86_64</p>
  
  <p>I have already asked this question <a href="https://stackoverflow.com/questions/38011530/xinternatom-and-xgetselectionowner-was-not-declared-in-this-scope">here</a> and I realised the problem associated with that based on the answer to the question.</p>
  
  <p>The actual problem is 
      <code>qx11info_x11.cpp: In static member function ‘static bool QX11Info::isCompositingManagerRunning()’:
  **qx11info_x11.cpp:386:108: **error: ‘XInternAtom’ was not declared in this scope**
           if (XGetSelectionOwner(QX11Info::display(), XInternAtom(QX11Info::display(), "_NET_WM_CM_S0", false)))**                                                                                                            ^
  **qx11info_x11.cpp:386:109: error: **‘XGetSelectionOwner’ was not declared in this scope**
           if (XGetSelectionOwner(QX11Info::display(), XInternAtom(QX11Info::display(), "_NET_WM_CM_S0", false)))**.</code></p>
  
  <p>The actual problem is with the <code>qt</code> module <code>qtx11extras</code>, which does not recognize the <code>XGetSelectionOwner</code> and <code>XInternAtom</code>. But my Linux box has the X11/Xlib.h installed. Even providing the Xlib.h in the included path during compilation did not help. So updated the file <code>qtx11extras/src/x11extras/qx11info_x11.cpp</code> to include <code>#include &lt;X11/Xlib.h&gt;</code>, it compiles successfully now. Do we see any issues with this approach.</p>