IIUC, Drew was offering an implementation of symmetric char folding,
whereas the release blocking aspect of this bug is to add a
char-folding-ad-hoc variable.

On Sat, 14 May 2016 5:45 pm Juri Linkov, <juri@linkov.net> wrote:

> >> I mean a char-folding customization that allows a search
> >> for “ä” match “a”.  Is this already possible?
> >
> > It sounds like you are asking for symmetric char folding: being
> > able to use any of the various A's that make up the A-characters
> > equivalence class as a search pattern and find any of those
> > characters.
> >
> > If so, I implemented that (one way, at least), and in emacs-devel
> > I proposed such behavior as a togglable option.
> >
> > It is trivial to try it, if you like: character-fold+.el.
> > http://www.emacswiki.org/emacs/download/character-fold%2b.el
> >
> > (A toggle command for it, `isearchp-toggle-symmetric-char-fold',
> > is defined in isearch+.el:
> > http://www.emacswiki.org/emacs/download/isearch%2b.el.)
>
> I'm starting to recollect all the remaining pieces to finish this
> release blocking issue, but I can't download this library,
> because the link is broken and it seems the whole site is down.
>
> Drew, could you please send the latest version as an attachment?
>