Add one-line GPL boilerplate to numerous (but not all yet) source files.
diff --git a/coreutils/od.c b/coreutils/od.c
index 8cd34bb..1149ef1 100644
--- a/coreutils/od.c
+++ b/coreutils/od.c
@@ -6,19 +6,7 @@
* Copyright (c) 1990
* The Regents of the University of California. All rights reserved.
*
- * 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 of the License, 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; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*
* Original copyright notice is retained at the end of this file.
*/