The POSIX CLOCK_MONOTONIC currently has only 1/HZ resolution.  Further, it is
tied to jiffies (i.e.  is a restatment of jiffies) rather than "xtime" or the
gettimeofday() clock.

This patch changes CLOCK_MONOTONIC to be a restatment of gettimeofday() plus
an offset to remove any clock setting activity from CLOCK_MONOTONIC.  An
offset is kept that represents the difference between CLOCK_MONOTONIC and
gettimeofday().  This offset is updated when ever the gettimeofday() clock is
set to back the clock setting change out of CLOCK_MONOTONIC (which by the
standard, can not be set).

With this change CLOCK_REALTIME (a direct restatement of gettimeofday()),
CLOCK_MONOTONIC and gettimeofday() will all tick at the same time and with
the same rate.  And all will be affected by NTP adjustments (save those which
actually set the time).