[clutter] Fix definition of ClutterEventExtender

[Emmanuele Bassi <ebassi src gnome org>]

commit a166cc9f35463f6ed79425de237df5e994eebaef
Author: Emmanuele Bassi <ebassi gnome org>
Date:   Wed Dec 9 12:42:55 2015 +0000

    Fix definition of ClutterEventExtender
    
    The interface vtable structure is missing the GTypeInterface parent, and
    GObject is complaining about it, as it should.

 clutter/clutter-device-manager-private.h |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/clutter/clutter-device-manager-private.h b/clutter/clutter-device-manager-private.h
index 9c42450..4aa1693 100644
--- a/clutter/clutter-device-manager-private.h
+++ b/clutter/clutter-device-manager-private.h
@@ -156,6 +156,8 @@ typedef struct _ClutterEventExtenderInterface ClutterEventExtenderInterface;
 
 struct _ClutterEventExtenderInterface
 {
+  GTypeInterface g_iface;
+
   void (* copy_event_data) (ClutterEventExtender *event_extender,
                             const ClutterEvent   *src,
                             ClutterEvent         *dest);