[glibmm/gmmproc-refactor] Add an unwrap_copy overload for references.

[Krzesimir Nowak <krnowak src gnome org>]

commit 0a8d991b175a3ec8d81539ccae4ee8f61dcf7b2b
Author: Krzesimir Nowak <qdlacz gmail com>
Date:   Sun Jul 22 15:59:26 2012 +0200

    Add an unwrap_copy overload for references.
    
    It is provided mainly for consistency - it simply calls gobj_copy()
    method.

 glib/glibmm/wrap.h |    9 +++++++++
 1 files changed, 9 insertions(+), 0 deletions(-)
---
diff --git a/glib/glibmm/wrap.h b/glib/glibmm/wrap.h
index 3d4eb74..cf216fe 100644
--- a/glib/glibmm/wrap.h
+++ b/glib/glibmm/wrap.h
@@ -160,6 +160,15 @@ const typename T::BaseObjectType* unwrap(const Glib::RefPtr<const T>& ptr)
 }
 
 /** Get the underlying C instance from the C++ instance and acquire a
+ * reference.
+ */
+template <class T> inline
+typename T::BaseObjectType* unwrap_copy(const T& ref)
+{
+  return ref.gobj_copy();
+}
+
+/** Get the underlying C instance from the C++ instance and acquire a
  * reference.  This is just like calling gobj_copy(), but it does its own
  * check for a NULL pointer.
  */