Fixed XCB build with -no-opengl

Task-number: QTBUG-30115
Change-Id: I1651a1cdda2a5370e23fabe631b0742a617631c0
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@digia.com>

src/plugins/platforms/xcb/qxcbnativeinterface.cpp

@@ -58,7 +58,9 @@
 #include "qglxintegration.h"
 #endif
 
-#ifndef XCB_USE_XLIB
+#ifdef XCB_USE_XLIB
+#  include <X11/Xlib.h>
+#else
 #  include <stdio.h>
 #endif