Y2K is long gone. Time to deprecate time.c?

[Ethan M. <merritt@u.washington.edu>]

A recent report on the newsgroup of gnuplot hanging turns out to be due
to a comedy of coding errors that I won't go into here, but ultimately
the hang is due to the routine ggmtime() in time.c 

ggmtime() stupidly calculates time by incremental subtraction from a target date
given in seconds.  If the target date is large, say 10^12, a single call can take
a minute to return.  If the target date is even larger, say 10^38, it would take
approximately 10^22 years to return from a single date calculation.
And guess what the default initial value is ;-\ ;-\ ;-\

The thing is, the routines in time.c are marked in the header as
being protection against possible Y2K problems in the POSIX time
routines provided by a system library.  Their use is under the control
of USE_SYSTEM_TIME, which currently defaults to being undefined.

Now that Y2K is past and gone, can we define USE_SYSTEM_TIME by default
and go back to using the standard POSIX routines?

If not that, should we put a sanity check in the time routines
limiting the accessible future to, say, the first 1.e10 seconds of the epoch?

-- 
Ethan A Merritt