bug#29872: 26.0.90; `man' output encoding, hyphen chars

[Drew Adams <drew.adams@oracle.com>]

> > > What about the below, does that work?
> > >   (let ((locale-coding-system 'utf-8))
> > >     (man "find"))
> >
> > Yes!  With `emacs -Q', loading the two files mentioned,
> > and then evaluating that sexp, the `man' output is correct:
> > hyphens appear as they should - that is:
> >
> >   name: HYPHEN
> >   general-category: Pd (Punctuation, Dash)
> >   decomposition: (8208) ('‐')
> >
> > What should I then change in, say, `setup-cygwin.el',
> > to make that happen?  (Or does something need to be
> > changed in Emacs itself?)
> 
> For Emacs 26, I've just committed a change that introduces a new
> defcustom, Man-coding-system, which you can customize to utf-8 to get
> the correct behavior in your case.  For older versions of Emacs, you
> will need to use a separate command that invokes 'man' as shown above,
> because man.el unconditionally uses locale-coding-system for that, and
> locale-coding-system on MS-Windows can never be UTF-8.

Thank you.  I assume that you'll mention this in NEWS.
I wonder whether it is something that I should set in
`setup-cygwin.el' or just tell users there, in a comment,
that they will need to customize it.

Leavning aside, for the moments, arguments about whether
code should mess with user options, can you say when it
is appropriate, typically, for a Windows user to customize
that option?  Does it have to do with whether Cygwin is
used, for instance (with a non-Cygwin Emacs)?  Or does
the option default value depend on the platform perhaps?