Support unix domain sockets under Win10

[casabre]

According to the following blog article, Win10 supports now AF_UNIX domain sockets. If I use ipc://, a not supported socket type will be reported. Thus, could please extend the compatible Win10 sockets to AF_UNIX as well. The support of the utilized Win10 version can be checked by sc query afunix

[minrk]

pyzmq doesn't limit libzmq's ipc support, it passes URLs directly to libzmq. so I think this is an issue for libzmq to deal with, unless it's pyzmq's bundled libzmq that's not setting necessary flags.

[casabre]

@minrk Thanks for the update. I will raise another issue at libzmq and link it.