Fix build with Mesa EGL

Mesa EGL headers include X11 headers, which may #define Bool.

Change-Id: I17379c24bfb7bac809b92f4c2a41298de00a972c
Reviewed-by: Andrew den Exter <andrew.den.exter@qinetic.com.au>

src/plugins/videonode/egl/qsgvideonode_egl.h

@@ -50,6 +50,10 @@
 #include <EGL/egl.h>
 #include <EGL/eglext.h>
 
+#ifdef Bool
+#  undef Bool
+#endif
+
 QT_BEGIN_NAMESPACE
 
 class QSGVideoMaterial_EGL : public QSGMaterial