3661 Sync mDNS with upstream
Reviewed by: Richard Lowe <richlowe@richlowe.net>
Approved by: Robert Mustacchi <rm@joyent.com>

2933 compiler warning gags need better granularity
Reviewed by: Eric Schrock <eric.schrock@delphix.com>
Approved by: Garrett D'Amore <garrett@damore.org>

PSARC 2005/562 Multicast DNS and Service Discovery
6550311 Multicast DNS and service discovery support