net: fix windows constants to make them public for net.unix usage

[GGRei]

Following this post: forum_discuss

It was not possible to use or compile code containing calls to the "net.unix" library on a Windows environment ( in my case, Windows 10). The errors encountered were:

v/vlib/net/unix/stream.c.v:73:54: error: constant 'net.msg_nosignal' is private
C.photon_send(c.sock.handle, ptr, remaining, net.msg_nosignal, c.write_timeout)

v/vlib/net/unix/stream.c.v:75:47: error: constant 'net.msg_nosignal' is private
C.send(c.sock.handle, ptr, remaining, net.msg_nosignal)

v/vlib/net/unix/stream.c.v:380:47: error: constant 'net.fionbio' is private
net.socket_error(C.ioctlsocket(handle, net.fionbio, &t))!

v/vlib/net/unix/stream.c.v:493:47: error: constant 'net.fionbio' is private
net.socket_error(C.ioctlsocket(sockfd, net.fionbio, &t))!

Test code to replicate the error:

module main

import net.unix

fn main() {
	println("test")
}

To address these issues, the affected constants have been made public in net_windows.c.v file.

I did not add a test file as merely importing 'net.unix' in the code was sufficient to trigger the previously mentioned errors. However, if required, I am ready to provide it.