bug#56712: 29.0.50; x-dnd-tests-do-direct-save fails on Cygwin

[Eli Zaretskii]

> Cc: 56712@debbugs.gnu.org
> Date: Sun, 24 Jul 2022 10:26:30 +0800
> From:  Po Lu via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> 
> Ken Brown <kbrown@cornell.edu> writes:
> 
> > Sorry, I'm not immediately seeing how to do this in the context of the
> > test. Could you be more explicit?
> 
> I suggest adding some code here, in x-dnd.el:
> 
>       (condition-case nil
>           (progn
>             (copy-file x-dnd-xds-current-file
>                        local-name t)
>             (when (equal x-dnd-xds-current-file
>                          dnd-last-dragged-remote-file)
>               (dnd-remove-last-dragged-remote-file)))
>         (:success '(STRING . "S"))
>         (error '(STRING . "E")) <--- add code here
> 
> to print out the error that is causing it to reply with "E".

Maybe it is worth our while to convert this to a debugging code which
would collect the information given some variable setting?  Similar to
what other packages do, like Tramp?