[gtk/wip/ebassi/shortcut] Bring back gtk_widget_buildable_custom_tag_end

[Matthias Clasen <matthiasc src gnome org>]

commit 62f4f3400bf6bdba1b7fd2500c3d0fd3adc204e6
Author: Matthias Clasen <mclasen redhat com>
Date:   Sun Feb 9 15:26:28 2020 -0500

    Bring back gtk_widget_buildable_custom_tag_end
    
    Buildable implementations assume tha they can chain
    up. Removing the default implementation break that

 gtk/gtkwidget.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)
---
diff --git a/gtk/gtkwidget.c b/gtk/gtkwidget.c
index 65b15bb9a3..cccfa40ee8 100644
--- a/gtk/gtkwidget.c
+++ b/gtk/gtkwidget.c
@@ -674,6 +674,11 @@ static gboolean         gtk_widget_buildable_custom_tag_start   (GtkBuildable
                                                                  const gchar        *tagname,
                                                                  GtkBuildableParser *parser,
                                                                  gpointer           *data);
+static void             gtk_widget_buildable_custom_tag_end     (GtkBuildable       *buildable,
+                                                                 GtkBuilder         *builder,
+                                                                 GObject            *child,
+                                                                 const gchar        *tagname,
+                                                                 gpointer            data);
 static void             gtk_widget_buildable_custom_finished    (GtkBuildable       *buildable,
                                                                  GtkBuilder         *builder,
                                                                  GObject            *child,
@@ -8820,6 +8825,7 @@ gtk_widget_buildable_interface_init (GtkBuildableIface *iface)
   iface->get_internal_child = gtk_widget_buildable_get_internal_child;
   iface->parser_finished = gtk_widget_buildable_parser_finished;
   iface->custom_tag_start = gtk_widget_buildable_custom_tag_start;
+  iface->custom_tag_end = gtk_widget_buildable_custom_tag_end;
   iface->custom_finished = gtk_widget_buildable_custom_finished;
   iface->add_child = gtk_widget_buildable_add_child;
 }
@@ -9363,6 +9369,15 @@ gtk_widget_buildable_custom_tag_start (GtkBuildable       *buildable,
   return FALSE;
 }
 
+static void
+gtk_widget_buildable_custom_tag_end (GtkBuildable  *buildable,
+                                     GtkBuilder    *builder,
+                                     GObject       *child,
+                                     const gchar   *tagname,
+                                     gpointer       data)
+{
+}
+
 static void
 gtk_widget_buildable_finish_layout_properties (GtkWidget *widget,
                                                GtkWidget *parent,