bug#16429: EMACSDATA in the MS Windows registry can interfere with building

[Eli Zaretskii <eliz@gnu.org>]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: 16429@debbugs.gnu.org, Eli Zaretskii <eliz@gnu.org>
> Date: Fri, 20 May 2022 04:15:55 +0200
> 
> Glenn Morris <rgm@gnu.org> writes:
> 
> > 0cbc41322e clearly adds nothing relevant over e088b01d29.
> > so the comments from https://debbugs.gnu.org/16429#43 presumably still apply.
> 
> This was:
> 
> > Fixed for POSIX platforms.
> > Leaving open with downgraded severity since the MS Windows registry
> > could presumably still be a problem.
> 
> Eli, is there something we should do here on Windows hosts, or is
> defining these variables in the registry just a user error?

I see no reliable way of avoiding the effect of Registry settings on
incompatible Emacs versions.  People who want to be able to run
different Emacs versions on the same machine, including the capability
of building newer versions, should NOT use the Registry for these
settings.  We modified the addpm installation program some time ago to
not create any Registry settings that didn't already exist for this
very reason.

So I've now updated the Emacs manual with the advice not to use the
Registry, and I'm therefore closing this bug.