bug#33587: [PROPOSED] Default to disabling ImageMagick

[Glenn Morris]

David Engster wrote:

> Question is: will disabling Imagemagick by default also have an impact
> on how Emacs is shipped in distributions?

I don't know. It depends whether they go with the default configure
options or not.

> I don't think so, at least as long as they don't drop Imagemagick
> completely.

Note that Red Hat Enterprise Linux 8 _will_ drop ImageMagick completely
(though it will probably be available from an add-on repository),
presumably because they don't feel able to keep up with the security
issues. That's what prompted me to first raise this in

http://lists.gnu.org/r/emacs-devel/2018-12/msg00036.html

> If for instance Debian has to take care of Imagemagick security issues
> anyway, why shouldn't Emacs link to it?

(For reference:
https://security-tracker.debian.org/tracker/source-package/imagemagick )

Because one can never guarantee all security issues are fixed, and if a
project has a history of having a lot of them, it may be considered
likely to be insecure. Also there are the various Emacs crash reports
due to ImageMagick.