Proposed asctime-related changes

[Paul Eggert]

"Clive D.W. Feather" <clive at demon.net> writes:

> Doesn't matter for defensive coding. Okay, a value of -INT_MAX will print
> as "Tue" rather than "???", but who cares?

We're talking about code that attempts to defend against nonexistent
system bugs of a class that one cannot defend against in general.  So
to some extent we've gone off the deep end already.  As long as we're
going to such extremes, we might as well have the code output an
appropriate danger signal (in this case "???") whenever any underlying
problem can easily be detected.