bug#19259: [External] : Re: bug#19259: 25.0.50; Be able to use `compare-windows' in either direction

[Drew Adams]

> > Especially when `compare-windows' is used repeatedly (e.g. bound to a
> > repeatable key etc.), it can be helpful to be able to sometimes
> > compare backward, toward bob, instead of always forward, toward eob.
> > Please add this enhancement.
> 
> A few days after this bug report (apparently),
> `compare-windows-get-window-function' was added:
> 
> commit 96e6fd3c155b1851e0acd477789535a45b8d3187
> Author:     Juri Linkov <juri@linkov.net>
> AuthorDate: Fri Dec 5 02:50:41 2014 +0200
> 
>     Compare with the most recently used window by default.
> 
>     * lisp/vc/compare-w.el (compare-windows-get-window-function):
>     New defcustom.
> 
> This can be redefined by the user to respond to `C-u' and the like, so I
> don't think there's anything more to do here, and I'm closing this bug
> report.

So your decision is "won't fix".  Telling users they
can, essentially, redefine the command is not what
this request was about.

The request is clearly about fixing `compare-windows'
so that it can go either way - acting like `ediff'.
It specifically mentions `ediff' as a model behavior
in this regard.