Is there a neat way for a process to sleep until modem signal on the RI
line is detected?  TIOCMGET will tell me whether the line is active now,
but I would like the system to tell me when it is active, rather than
having to repeatedly poll.

Any ideas?  Am I right in thinking that Linux has a couple of extra ioctls
for doing this?  Do I need to hack these into NetBSD or is there Another
Way (tm)?

Thanks,

David.