when ttselect() is improved. This requires using an array of tty structs
and not using ttymalloc().
Fix an off by 1 error. Some caclulations seem to be off by a factor
of NCY. NCY defaults to 16, which gives 256 tty structs occupying
0xd000 bytes. The minor number encoding only allows 16 ttys.
Update the types of timeout functions to 2.0.
adapted to FreeBSD by Heikki Suonsivu <hsu@cs.hut.fi>.
Submitted by: Andrew Werple <andrew@werple.apana.org.au> and
Heikki Suonsivu <hsu@cs.hut.fi>
Obtained from: NetBSD