* fhandler.h (enum conn_state): Add connect_failed state.
* fhandler_socket.cc (fhandler_socket::connect): Set connect_state to
connect_failed when connect failed.
* poll.cc (poll): Change errno to EINVAL if allocating memory fails,
according to SUSv3. Add socket descriptors always to except_fds. Test
for failed connect and set revents flags appropriately.
* select.cc (set_bits): Set connect_state to connect_failed when
select indicates failed nonblocking connect.
(fhandler_dev_null::select_except): Set except_ready to false so that
/dev/null is not always in except state.
(peek_socket): Fix bogus conditional.
(fhandler_socket::select_write): Treat all connect_states except
unconnected equivalent to return consistent results.
(fhandler_windows::select_except): Set except_ready to false so that
/dev/windows is not always in except state.