Find the real name of the tty using ttyname_r(3) instead of
opening "/dev/tty" which causes trouble if the fd doesn't point to the
controlling terminal.
PR-URL: https://github.com/libuv/libuv/pull/779
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Saúl Ibarra Corretgé <saghul@gmail.com>