socket :: NativeSocket :: poll_hup_err
POLLHUP|POLLERRA return value of 0 means there is no errors.
	# Poll this socket with `POLLHUP|POLLERR`
	#
	# A return value of 0 means there is no errors.
	fun poll_hup_err: Int `{
		struct pollfd fd = {*self, POLLHUP|POLLERR, 0};
		int res = poll(&fd, 1, 0);
		return res;
	`}
					lib/socket/socket_c.nit:181,2--188,3