Mac OS cannot announce?

[liuzhen]

I tried on my Mac, it always returns {error, eaddrnotavail}.

If I change to:

gen_udp:open(0, [binary])

it works like a charm.

Any ideas?

[Licenser]

Those are two very different things,
mdns needs to bind a and (re-use) for port 5353, OS X has had some strange behaviour on that in the past.

[liuzhen]

PR acceptable?