clock past the End of Time.
If time_t is 32 bits, then the "End of Time" is Jan 18/19 2038
(depending on time zone).
This code copes with RTC's past the end of time if time_t is an int32
or less. It just forces the time back to 2037. This will let users
with screwed up clocks to at least boot and function long enough to
set their clocks to something sane.
This kludge is conditioned on an
if (sizeof(time_t) <= sizeof(int32_t))
which will automatically optimize the code out once we switch time_t
to a 64 bit quantity, which should happen well before 2037.
Patch based on code from Michael C. Richardson, with help from
Allen Briggs who pointed out a fencepost error.