Add support for Windows named-pipes to Host_lwt_unix
Add support for Windows named-pipes to Host_lwt_unix

Note that Host_uwt already supports these via libuv.

Signed-off-by: David Scott <63c9eb0ea83039690fefa11afe17873ba8278a56@docker.com>

djs55/vpnkit,djs55/vpnkit,djs55/vpnkit