Update to openresolv-3.11.0 with the following changes:

*  notify avahi-daemon of resolv.conf being changed
  *  notify mdnsd of resolv.conf being changed

external/bsd/openresolv/dist/README.md

@@ -62,3 +62,7 @@ openresolv ships with helpers for:
 See the
 [configuration section](https://roy.marples.name/projects/openresolv/config)
 for more details.
+
+If openresolv updates `/etc/resolv.conf` it can notify the following of this:
+  *  [Bonjour (mdnsd)](https://developer.apple.com/bonjour/)
+  *  [avahi](http://www.avahi.org/)

external/bsd/openresolv/dist/avahi-daemon.in

@@ -0,0 +1,32 @@
+#!/bin/sh
+# Copyright (c) 2007-2020 Roy Marples
+# All rights reserved
+
+# avahi-daemon notifier for resolvconf libc subscriber
+
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+#     * Redistributions of source code must retain the above copyright
+#       notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+#       copyright notice, this list of conditions and the following
+#       disclaimer in the documentation and/or other materials provided
+#       with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+: ${avahi_daemon_pidfile:=/var/run/avahi-daemon/pid}
+if [ -s "$avahi_daemon_pidfile" ]; then
+	kill -HUP $(cat "$avahi_daemon_pidfile")
+fi

external/bsd/openresolv/dist/mdnsd.in

@@ -0,0 +1,32 @@
+#!/bin/sh
+# Copyright (c) 2007-2020 Roy Marples
+# All rights reserved
+
+# mdnsd notifier for resolvconf libc subscriber
+
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+#     * Redistributions of source code must retain the above copyright
+#       notice, this list of conditions and the following disclaimer.
+#     * Redistributions in binary form must reproduce the above
+#       copyright notice, this list of conditions and the following
+#       disclaimer in the documentation and/or other materials provided
+#       with the distribution.
+#
+# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+: ${mdnsd_pidfile:=/var/run/mdnsd/mdnsd.pid}
+if [ -s "$mdnsd_pidfile" ]; then
+	kill -HUP $(cat "$mdnsd_pidfile")
+fi