Sync google3/third_party/mDNSResponder with this version.

This includes updating mDNSResponder to a more recent version.
Additionally, we introduce a make target that is suitable for
GmsCore to use. Soon GmsCore will embed a version of mDNS
locally for its 'Local App Connections API'.

Change-Id: I95c1e39beb45c06256b1c7959b34af24e827135a
12 files changed