bug#5050: 23.1; efiff: Displaying bytes instead of characters in messages

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: sebastian_rose@gmx.de,  stephen.berman@gmx.net,  5050@debbugs.gnu.org
> Date: Thu, 20 Aug 2020 22:01:57 +0200
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > And anyway, Stephen just answered my question, and the diffs are
> > displayed correctly with non-ASCII characters, not as raw bytes.  So
> > there's more here than meets the eye.
> 
> They are, but the output in that buffer is just raw bytes -- no matter
> whether the output is from stderr or stdout.  There must be a decoding
> thing that takes place later, but I'm still looking for where that
> happens.  (I'm wholly unfamiliar with the ediff code.)
> 
> When I've found that, the fix would be to apply whatever it's doing to
> the error buffer, too...

Wait, the problematic text appears in the Ediff error buffer, right?
So we should perhaps simply decode it?  Does evaluating the below in
that buffer fixes the problem?

  M-: (decode-coding-region (point-min) (point-max) 'undecided) RET