[cluttermm] A vfunc fix.

[Murray Cumming <murrayc src gnome org>]

commit e8d739ef088077d9fd08915bc4ebd0988571bc61
Author: Murray Cumming <murrayc murrayc com>
Date:   Thu Mar 27 11:40:26 2014 +0100

    A vfunc fix.

 clutter/src/constraint.hg |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/clutter/src/constraint.hg b/clutter/src/constraint.hg
index 6e67b4e..c6bb172 100644
--- a/clutter/src/constraint.hg
+++ b/clutter/src/constraint.hg
@@ -52,7 +52,7 @@ public:
   //_WRAP_CREATE()
 
 protected:
-   _WRAP_VFUNC(void update_allocation(Glib::RefPtr<Actor>& actor, ActorBox& allocation), update_allocation)
+   _WRAP_VFUNC(void update_allocation(const Glib::RefPtr<Actor>& actor, ActorBox& allocation), 
update_allocation)
 };
 
 }