--- gtk+-2.24.33/gtk/gtkscalebutton.c.orig
+++ gtk+-2.24.33/gtk/gtkscalebutton.c
@@ -425,6 +425,10 @@
   return object;
 }
 
+void
+gtk_scale_button_set_orientation (GtkScaleButton *button,
+                                  GtkOrientation  orientation);
+
 static void
 gtk_scale_button_set_property (GObject       *object,
 			       guint          prop_id,