bug#12430: Glitches caused by addition of psec to timers

[Glenn Morris]

Paul Eggert wrote:

> I don't see how rounding errors could be avoided.  As a trivial example, if I
> write '0.001' in Emacs Lisp, I get a number slightly bigger than 0.001
> due to rounding error, so the underlying OS primitives (which always
> get the ceiling of the delay request) would see two nanoseconds rather
> than the one that I wanted.  OK, so it's only a nanosecond off, but
> the point is that Emacs shouldn't be munging the low-order
> bits of users' requests.

Maybe you should future-proof the timer format by jumping to units of
Planck time rather than picoseconds... I supposed you still need to
worry about portability between Universes though (please address in
Gnulib ASAP).

(I wonder when the first Emacs application will be written that has a
legitimate need to schedule a timer event with sub-millisecond
resolution.)