RFC: adding fd-passing to win32

[Lawrence D'Oliveiro]

On Tue, 23 Aug 2022 15:35:06 -0300, Thiago Macieira wrote:

> Do note that's not a Unix feature, but a Linux one.

IEEE 1003.1, otherwise known as POSIX. Looking at a copy of “Issue 6”
(from 2001), the “Base Definitions” volume, page 332:

    The <stropts.h> header shall define the strrecvfd structure
    that includes at least the following members:
    int fda
     Received file descriptor.
    uid_t  uid
     UID of sender.
    gid_t  gid
     GID of sender.

Page 333:

    I_RECVFD Get a file descriptor sent via I_SENDFD.

Any questions?