bug#29766: 25.3; REGRESSION, Dired on MS Windows, switches -alF

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

> > > We already have plenty of such customization options
> > > in ls-lisp.el, had them for a long time.
> >
> > What option(s) in ls-lisp.el correspond to such an alist?
> 
> What alist and for which purpose?  You never explained that.

As I said:

  But since different platforms have
  (apparently) such different outside-Emacs behaviors,
  perhaps an alist of values, keyed by platform in some
  way, would be better.  Then the defaults for common
  platforms could be preconfigured according to what
  users of those platforms might expect.  And a user
  of multiple platforms could opt for either the same
  behavior everywhere or different behaviors here and
  there.  Just something to think about, I guess.

If you see no way to have alist keys that can be
used to specify per-platform behavior, then that
suggestion is perhaps not feasible.

But otherwise, it could be useful.  An alist entry
of, say, (windows-nt . compare-strings) would have
the effect, when (eq system-type 'windows-nt), of
using `compare-strings' to sort files.  An entry
of (windows-nt . string-collate-lessp) would
instead use ` string-collate-lessp' on MS Windows.

The same user could have preferred settings for
multiple platforms.  The default alist value could
be whatever you like.

> > I don't see any.  And if there is already such an option,
> > let alone plenty of them, then why did we add
> > `ls-lisp-use-string-collate'?
> 
> I don't see how an alist could replace
> ls-lisp-use-string-collate.

See above.  Change the value of the option from
Boolean to alist.  Get the sort predicate from
the alist, checking the key against the current
platform (or whatever - perhaps `system-type'
is not the only reasonable test).