video: Add header include guard

gtk/gtkmediacontrols.h

@@ -20,6 +20,10 @@
 #ifndef __GTK_MEDIA_CONTROLS_H__
 #define __GTK_MEDIA_CONTROLS_H__
 
+#if !defined (__GTK_H_INSIDE__) && !defined (GTK_COMPILATION)
+#error "Only <gtk/gtk.h> can be included directly."
+#endif
+
 #include <gtk/gtkmediastream.h>
 #include <gtk/gtkwidget.h>
 

gtk/gtkvideo.h

@@ -20,6 +20,10 @@
 #ifndef __GTK_VIDEO_H__
 #define __GTK_VIDEO_H__
 
+#if !defined (__GTK_H_INSIDE__) && !defined (GTK_COMPILATION)
+#error "Only <gtk/gtk.h> can be included directly."
+#endif
+
 #include <gtk/gtkmediastream.h>
 #include <gtk/gtkwidget.h>