> <@trungnt2910:matrix.org> `TIOCEXL`: Places the current TTY into exclusive mode, so that no one except root (oops probably not so useful on Haiku) can re-`open` the TTY.
> `TIOCINQ`: Gets the number of input bytes available.
> `TIOCOUTQ`: Gets the number of output bytes buffered.

If there aren't any reasons _not_ to include these on Haiku I'll have a look at the `termios` code tomorrow. Otherwise, if there are reasons not to include them (or if they're too complicated and not worth the effort) I'll just stub them out.