add definitions for afunix.h

[fanzeyi]

Since Windows 17063, there is UNIX domain socket support in Windows. Along with the support afunix.h is added to define SOCKADDR_UN struct for creating UNIX domain sockets.

This pull request adds the definition mirrors afunix.h in Windows SDK.

See "AF_UNIX comes to Windows"

Windows header file location: C:\Program Files (x86)\Windows Kits\10\Include\10.0.19041.0\shared\afunix.h

[Thomasdezeeuw]

Any updates on this? We need this in socket2: rust-lang/socket2#249.

[fanzeyi]

Not sure what I can do to get this land. winapi-rs seems to be completely stagnated now. :(

There was some discussion about moving winapi-rs to the nursery but nothing has happened it seems.

[elmarco]

nice! I came up with practically the same patch without knowing you add a MR.

I think you should add the common top header:

// Licensed under the Apache License, Version 2.0
// <LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
// All files in the project carrying such notice may not be copied, modified, or distributed
// except according to those terms.
//! Definitions for the AF_UNIX socket address family.