Update to FreeBSD head 2018-02-01

Git mirror commit d079ae0442af8fa3cfd6d7ede190d04e64a2c0d4.

Update #3472.

freebsd/lib/libc/resolv/res_debug.h

@@ -1,4 +1,6 @@
-/*
+/*-
+ * SPDX-License-Identifier: ISC
+ *
  * Copyright (c) 2004 by Internet Systems Consortium, Inc. ("ISC")
  * Copyright (c) 1999 by Internet Software Consortium.
  *
@@ -13,6 +15,8 @@
  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ * $FreeBSD$
  */
 
 #ifndef _RES_DEBUG_H_