>
> So, getting back to the question: Do we have some "standard" workaround? 
> I don't actually need to represent times from the early 20th century, 
> but I need to compute NTP timestamps.  I can come up with my own 
> workaround (e.g. hardcoding as a "magic constant" the number of seconds 
> between NTP's origin time and some arbitrary other origin time of my 
> choosing which 32bit systems can represent), but I was hoping we already 
> have something like that somewhere.
>

Apparently there is no standard workaround in Emacs.  So on a 32bit 
system, I would use the constant 2208988800 (25567 days times 86400 
seconds), to represent the difference in seconds between 1900-01-01 and 
1970-01-01 (epoch).  This constant is given in the very first NTP RFC [1], 
and doing this should be safe: the current NTP format (32 bits for the 
integer part) will work until Feb 7, 2036, that is, before 32-bit counting 
after epoch will stop working on Jan 19, 2038.

[1] https://tools.ietf.org/html/rfc868