fix(net): add NOSIGNAL to send options

This is a better default than not having it, since it turns errors that
would be signals into error values instead. We could take these as
options but given that we currently don't I think this at the very least
improves on the status quo.

core/net/errors_linux.odin

@@ -136,6 +136,7 @@ TCP_Send_Error :: enum c.int {
 	Interrupted               = c.int(linux.Errno.EINTR),        // A signal occurred before any data was transmitted. See signal(7).
 	Timeout                   = c.int(linux.Errno.EWOULDBLOCK),  // The send timeout duration passed before all data was sent. See Socket_Option.Send_Timeout.
 	Not_Socket                = c.int(linux.Errno.ENOTSOCK),     // The so-called socket is not an open socket.
+	Broken_Pipe               = c.int(linux.Errno.EPIPE),        // The peer has disconnected when we are trying to send to it
 }
 
 // TODO

core/net/socket_linux.odin

@@ -258,7 +258,7 @@ _send_tcp :: proc(tcp_sock: TCP_Socket, buf: []byte) -> (int, Network_Error) {
 	for total_written < len(buf) {
 		limit := min(int(max(i32)), len(buf) - total_written)
 		remaining := buf[total_written:][:limit]
-		res, errno := linux.send(linux.Fd(tcp_sock), remaining, {})
+		res, errno := linux.send(linux.Fd(tcp_sock), remaining, {.NOSIGNAL})
 		if errno != .NONE {
 			return total_written, TCP_Send_Error(errno)
 		}