some docs fixes for x86_64
diff --git a/COPYRIGHT b/COPYRIGHT
index d9975ec..92d8992 100644
--- a/COPYRIGHT
+++ b/COPYRIGHT
@@ -19,6 +19,9 @@
1994 David Burren. It is licensed under a BSD license compatible with
the GNU LGPL.
+The x86_64 port was written by Nicholas J. Kain. See individual files
+for their copyright status.
+
All files which have no copyright comments are original works
Copyright © 2005-2011 Rich Felker, the main author of this library.
The decision to exclude such comments is intentional, as it should be