type mismatches. There was no problem in practice (at least on 386's).
Don't cast NULL in calls to timeout functions. pcvt is fully prototyped
and doesn't support K&R.
Timeout functions take args of type `void *', so use magic numbers of
type `void *' for UPDATE_* to reduce the danger of wrong conversions.
Removed FreeBSD-pre-1.1-related TIMEOUT_FUNC_T macro. It was especially
bogus for the pre-1.1 case.