libwebsockets

windows: recent win10 support Unix Domain

Allow selection of Unix Domain Sockets on windows since it is supported
for the last couple of years on windows 10

https://devblogs.microsoft.com/commandline/af_unix-comes-to-windows/

... if only they could add a full set of posix pieces to go with it
(and abstract namespace UDS which doesn't work apparently) so that
the parts dealing with uid / gid don't have to be disabled.