Listening on IPv6 - free IPv4 too

[Hal Murray]

I was cleaning up a quirk, while I was at it, I added the IPv6 listener.  That 
turned into an interesting adventure.  By default, on most systems, it also 
listens on IPv4.  If you already have an IPv4 listener on that port, it fails 
with an Address already in use error.  There is a socket option to disable 
that - IPV6_V6ONLY

Can we depend on that behavior?  If yes, I can clean up some code.

It's in NetBSD and FreeBSD.


-- 
These are my opinions.  I hate spam.