bug#19302: 24.4.51; `date-to-time' fails after 2038

[Eli Zaretskii]

> From: Ivan Shmakov <ivan@siamics.net>
> Date: Tue, 09 Dec 2014 18:17:59 +0000
> 
>  > What do you do with time_t fields of 'struct stat', 'struct timeval',
>  > and other structures used by library functions?  They will still wrap
>  > around.
> 
>       How would that affect a function whose purpose is not to pass
>       such a time value to some library call?
> 
>       And when a value /is/ passed to the underlying platform, it can
>       be checked if it fits the target type, and the error signalled
>       if it doesn’t.

So such an Emacs will be broken anyway after 2038, because it will be
unable to interpret file attributes, use interval timers, etc.