bug#50572: 28.0.50; [PATCH] fix VC to find the responsible backend with the most specific path.

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: dgutov@yandex.ru,  50572@debbugs.gnu.org,  andrewjmoreton@gmail.com,
>   manuel@ledu-giraud.fr
> Date: Wed, 10 Nov 2021 13:59:24 +0100
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > Why isn't expand-file-name TRT?  If the file names are not absolute,
> > you cannot reliably compare their "depth" anyway.
> 
> For this particular thing, you probably need absolute paths.  But a
> general file-name-splitting functions should have that limitation.

We can always use "/\\" as SEPARATORS on MS-Windows, can't we?

Alternatively, we could loop with file-name-directory, I guess.

But if we want a function that returns the "depth" of a file in a
filesystem, then it will need to call expand-file-name internally
anyway, for the same reason I point out above, right?