gtk/: fully remove gtkalias hacks

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

gtk/gtkexpander.c

@@ -34,7 +34,6 @@
 #include "gtkprivate.h"
 #include <gdk/gdkkeysyms.h>
 #include "gtkdnd.h"
-#include "gtkalias.h"
 
 #define GTK_EXPANDER_GET_PRIVATE(o) (G_TYPE_INSTANCE_GET_PRIVATE ((o), GTK_TYPE_EXPANDER, GtkExpanderPrivate))
 
@@ -1743,6 +1742,3 @@ gtk_expander_get_label_widget (GtkExpander *expander)
 
   return expander->priv->label_widget;
 }
-
-#define __GTK_EXPANDER_C__
-#include "gtkaliasdef.c"