respective NetBSD driver for use with the genclock interface.
It's first use will be on sparc64 but it was also tested on alpha with
a preliminary patch to switch alpha to use the genclock code together
with this driver instead of the respective code in alpha/alpha/clock.c
and the rather MD mcclock(4). Using it on i386 and amd64 won't be that
hard but some changes/extensions to improve the genclock code in general
should be done first, e.g. add locking and make it easier to access the
NVRAM usually coupled with RTCs.
