slirp: clarify license of slirp files using SPDX: implicit via unstated

Add SPDX license identifier to clarify the license of files without
explicit license header.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/src/udp6.c b/src/udp6.c
index deffb48..6f9486b 100644
--- a/src/udp6.c
+++ b/src/udp6.c
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: BSD-3-Clause */
 /*
  * Copyright (c) 2013
  * Guillaume Subiron