bug#62420: 29.0.60; fns-tests-collate-strings fails on Cygwin

[Eli Zaretskii]

> Date: Sat, 25 Mar 2023 10:27:51 -0400
> Cc: 62420-done@debbugs.gnu.org
> From: Ken Brown <kbrown@cornell.edu>
> 
> On 3/25/2023 8:24 AM, Eli Zaretskii wrote:
> >> Date: Fri, 24 Mar 2023 10:52:45 -0400
> >> From: Ken Brown <kbrown@cornell.edu>
> >> Is this OK for the emacs-29 branch?
> > 
> > Yes, thanks.
> > 
> >> [Note: The test will still fail on current Cygwin after this patch; but
> >> that's because of a bug in Cygwin, which has been fixed in the
> >> development sources for Cygwin 3.5.]
> > 
> > Maybe mention this in comments?
> 
> Done.

Thanks.

> >  Bonus points for making it an
> > expected failure for Cygwin < 3.5, assuming the version of Cygwin
> > could be obtained by the test code.
> 
> I don't know how to get the version in Lisp.  I only know how to get it 
> in C, using uname.  If someone can tell me how to get it in Lisp, I'll 
> try to earn the bonus points.

What's the value of operating-system-release return in a Cygwin build?