qt: Ensure GL headers are included

Otherwise there may be no valid typedef of GLsync.

...
/usr/include/gstreamer-1.0/gst/gl/gstglfuncs.h:93:24: note: in definition of macro 'GST_GL_EXT_FUNCTION'
   ret (GSTGLAPI *name) args;
                        ^~~~
/usr/include/gstreamer-1.0/gst/gl/glprototypes/sync.h:33:23: error: 'GLsync' has not been declared
                      (GLsync sync))
                       ^~~~~~
...

https://bugzilla.gnome.org/show_bug.cgi?id=796879

diff --git a/ext/qt/gstqtgl.h b/ext/qt/gstqtgl.h
index 1f204ab..fd82b27 100644 (file)
--- a/ext/qt/gstqtgl.h
+++ b/ext/qt/gstqtgl.h
@@ -24,6 +24,7 @@
  * warnings/errors */
 
 #include <gst/gl/gstglconfig.h>
+#include <gst/gl/gstglfuncs.h>
 #include <QtCore/qglobal.h>
 #if (QT_VERSION >= QT_VERSION_CHECK(5, 9, 0))
 #include <QtGui/qtgui-config.h>