[ale] Cthreads on RedHat

[Tucker Balch]

Howdy, in trying to compile the latest version of Cthreads on my
Linux box (RH4), it croaks because it can't find poll.h .  A "man poll"
on SunOS reveals that it's for multiplexing i/o over a set of
file descriptors.  A "man poll" on linux draws a blank.  Any ideas?

Thanks,

--Tucker