[tz] strftime %s

[Garrett Wollman]

<<On Sun, 21 Jan 2024 21:45:41 -0800, Paul Eggert via tz <tz at iana.org> said:

> Also on typical platforms where int is 32 bits, localtime stops working 
> for time_t values greater than around 6.8e+16, so even 60-bit time_t is 
> overkill for today's platforms.

32 bits being clearly inadequate, what is the next available integer
type of greater width, that every implementation is required to
provide?  In POSIX, that's int64_t.  (I don't think given the
constraints on intN_t types you could have an int53_t although that's
clearly practical to implement if you have support for denormalized
IEEE doubles.)

-GAWollman