gtk/: fully remove gtkalias hacks

https://bugzilla.gnome.org/show_bug.cgi?id=623845

gtk/gtkseparatortoolitem.c

@@ -25,8 +25,6 @@
 #include "gtkintl.h"
 #include "gtktoolbar.h"
 #include "gtkprivate.h"
-#include "gtkalias.h"
-
 
 /**
  * SECTION:gtkseparatortoolitem
@@ -300,6 +298,3 @@ gtk_separator_tool_item_set_draw (GtkSeparatorToolItem *item,
       g_object_notify (G_OBJECT (item), "draw");
     }
 }
-
-#define __GTK_SEPARATOR_TOOL_ITEM_C__
-#include "gtkaliasdef.c"