'(c)' may not be a valid substitute for 'Copyright' in some legal
domains/interpretations. So be safe, since I obviously am asserting
copyright on my legal work.
Thus signed/unsigned conversion issues can't be a problem.
The extra range provided by ull isn't useful, either, since
we're dealing with uint32_t time_t seconds converted to ns,
which doesn't come close to exhausting the amount of post-epoch
ns that will be consumed until after 2100AD.
