Add license notice.

oldXMenu/insque.c

-/* Copyright (C) 2001, 2002, 2003, 2004, 2005,
-                 2006 Free Software Foundation, Inc.  */
+/* Copyright (C) 1993, 1994, 1995, 1996, 1997, 1998, 2001, 2002, 2003,
+                 2004, 2005, 2006 Free Software Foundation, Inc.
+
+This program is free software; you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 2, or (at your option)
+any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program; see the file COPYING.  If not, write to
+the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+Boston, MA 02110-1301, USA.  */
 
 /* This file implements the emacs_insque and emacs_remque functions,
-   copies of the insque and remque functions of BSD.  They and all
+   clones of the insque and remque functions of BSD.  They and all
    their callers have been renamed to emacs_mumble to allow us to
    include this file in the menu library on all systems.  */