bug#40407: [PATCH] slow ENCODE_FILE and DECODE_FILE

[Eli Zaretskii]

> From: Mattias Engdegård <mattiase@acm.org>
> Date: Mon, 6 Apr 2020 19:49:19 +0200
> Cc: hirofumi@mail.parknet.co.jp, handa@gnu.org, 40407@debbugs.gnu.org
> 
> > I prefer to wait for Handa-san's response, and meanwhile install the
> > least disruptive change, which just fixes the one aspect that got
> > broken.  Call me a coward, if you wish.
> 
> If so, the least disruptive change by far would be the two calls to 
> coding-system-put in my patch (along with the tests, of course).

Fine with me, but please say something about why we use 'put' instead
of specifying :ascii-compatible-p directly in the coding-system's
definition, and also add a FIXME there, since I hope this is not the
final word on that matter.

Thanks.