bug#17330: files.el cd-absolute overcome false negative from file-executable-p

[Eli Zaretskii <eliz@gnu.org>]

> From: Achim Gratz <Stromeko@nexgo.de>
> Date: Sat, 03 May 2014 11:35:01 +0200
> 
> But yes, you can totally have full access to a directory or file on a
> Windows box while all permission flags show that you don't (I guess that
> is also possible on UN*X, although I've never tried).  You'll never know
> until you actually try.

That's true (on Windows; I don't think it's possible on Unix), but why
is that an Emacs problem?  I think this problem should be communicated
to the Cygwin maintainers: an accessible directory should return
success from the faccessat call, because otherwise Posix-originated
programs such as Emacs will misbehave.

If the Cygwin maintainers will decide that this specific situation
(whose particulars as far as Windows ACL data of the directory in
question was never shown by the OP, by the way), then this would mean
it's either a cockpit error (i.e. the user shoot himself in the foot
by creating a security descriptor he shouldn't have), or that Cygwin
does not intend to support such situations in the first place.  Either
way, Emacs is not to blame here.