r5171: added support for "bind interfaces only" in nbtd. The solution was to

r5171: added support for "bind interfaces only" in nbtd. The solution was to
bind twice on each interface, once using the broadcast address and
once using the specific IP. We then only listen on the wildcard
address if we don't have "bind interface only" set. This also happens
to simplify the code that finds the right interface for an incoming
request.
(This used to be commit b3edf17281c5d82abb40dab817bf2de43f9f6c3f)