[gtkmm] Overlay: Add child properties.

[Murray Cumming <murrayc src gnome org>]

commit 000134d2d5b0ae8f515c697414f5b8a8a0122e1b
Author: Murray Cumming <murrayc murrayc com>
Date:   Tue Sep 15 10:48:27 2015 +0200

    Overlay: Add child properties.

 gtk/src/overlay.hg |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)
---
diff --git a/gtk/src/overlay.hg b/gtk/src/overlay.hg
index f409bb8..e0c1958 100644
--- a/gtk/src/overlay.hg
+++ b/gtk/src/overlay.hg
@@ -66,7 +66,9 @@ public:
 #m4 _CONVERSION(`GdkRectangle*',`Gdk::Rectangle&',`Glib::wrap($3)')
   _WRAP_SIGNAL(bool get_child_position(Gtk::Widget* widget, Gdk::Rectangle& allocation), 
"get-child-position")
 
-  // Gtk::Overlay has no properties nor vfuncs as of 3.2.
+  _WRAP_CHILD_PROPERTY("pass-through", bool)
+  _WRAP_CHILD_PROPERTY("index", int)
+
 };
 
 } // namespace Gtk