[mutter] x11/barrier: Fix build

[Jasper St. Pierre <jstpierre src gnome org>]

commit ef32bbdc99d82d42fa4bfa9b338809a2ca9fe254
Author: Jasper St. Pierre <jstpierre mecheye net>
Date:   Sat Jan 17 17:42:26 2015 -0800

    x11/barrier: Fix build
    
    We were missing the get_type() function.

 src/backends/x11/meta-barrier-x11.h |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/src/backends/x11/meta-barrier-x11.h b/src/backends/x11/meta-barrier-x11.h
index 802494c..9469fd8 100644
--- a/src/backends/x11/meta-barrier-x11.h
+++ b/src/backends/x11/meta-barrier-x11.h
@@ -50,6 +50,8 @@ struct _MetaBarrierImplX11Class
   MetaBarrierImplClass parent_class;
 };
 
+GType meta_barrier_impl_x11_get_type (void) G_GNUC_CONST;
+
 MetaBarrierImpl *meta_barrier_impl_x11_new (MetaBarrier *barrier);
 
 G_END_DECLS