[gtkmm] Wrap GtkSettings new properties as of 3.12

[Kjell Ahlstedt <kjellahl src gnome org>]

commit 77409e80e2c16c4c6d547ac06d26b18f9675f754
Author: Juan R. García Blanco <juanrgar gmail com>
Date:   Mon Feb 3 09:23:14 2014 +0100

    Wrap GtkSettings new properties as of 3.12
    
    * GtkSettings::gtk-decoration-layout property
    * GtkSettings::gtk-shell-shows-desktop property
    * GtkSettings::gtk-dialogs-use-header property

 gtk/src/settings.hg |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/gtk/src/settings.hg b/gtk/src/settings.hg
index b1ce4fa..6ae5429 100644
--- a/gtk/src/settings.hg
+++ b/gtk/src/settings.hg
@@ -104,6 +104,7 @@ public:
   _WRAP_PROPERTY("gtk-im-status-style", IMStatusStyle, deprecated "This setting is ignored.") //since 3.4
   _WRAP_PROPERTY("gtk-shell-shows-app-menu", bool) //since 3.4
   _WRAP_PROPERTY("gtk-shell-shows-menubar", bool) //since 3.4
+  _WRAP_PROPERTY("gtk-shell-shows-desktop", bool) //since 3.12
   _WRAP_PROPERTY("gtk-enable-primary-paste", bool) //since 3.6
 
   _WRAP_PROPERTY("gtk-menu-popup-delay", int, deprecated "This setting is ignored.") //since 3.4
@@ -132,6 +133,9 @@ public:
 
   _WRAP_PROPERTY("gtk-recent-files-enabled", bool)
   _WRAP_PROPERTY("gtk-primary-button-warps-slider", bool)
+
+  _WRAP_PROPERTY("gtk-decoration-layout", Glib::ustring) // since 3.12
+  _WRAP_PROPERTY("gtk-dialogs-use-header", bool) // since 3.12
 };
 
 } //namespace Gtk