Fix/Update copyright notices; Add SPDX annotation
Let's fix some erroneous/accidential references to wrong license,
update copyright information where applicable and introduce a
SPDX-License-Identifier to all files.
Change-Id: I39af26c6aaaf5c926966391f6565fc5936be21af
diff --git a/src/vty/buffer.c b/src/vty/buffer.c
index 1935aa1..e68e3a2 100644
--- a/src/vty/buffer.c
+++ b/src/vty/buffer.c
@@ -3,6 +3,8 @@
/*
* Copyright (C) 1998 Kunihiro Ishiguro
*
+ * SPDX-License-Identifier: GPL-2.0+
+ *
* This file is part of GNU Zebra.
*
* GNU Zebra is free software; you can redistribute it and/or modify