Fix compilation on Harmattan

Include X11 headers to get VisualID and other "types".

Change-Id: Idbb323329d346726b98312b1e02c9b199f2b7a65
Reviewed-on: http://codereview.qt-project.org/5928
Reviewed-by: Qt Sanity Bot <qt_sanity_bot@ovi.com>
Reviewed-by: Samuel Rødal <samuel.rodal@nokia.com>

src/platformsupport/eglconvenience/qxlibeglintegration.cpp

@@ -39,6 +39,9 @@
 **
 ****************************************************************************/
 
+#include <X11/X.h>
+#include <X11/Xlib.h>
+#include <X11/Xutil.h>
 #include "qxlibeglintegration_p.h"
 
 static int countBits(unsigned long mask)