Segfault after bad value for meta-prefix-char

[Peter Heslin]

Since I never use the ESC key in Emacs, I was experimenting with
trying to see if I could bind it to something like
keyboard-escape-quit, which I might find useful.

Someone in the archives of the xemacs mailing list posted this code:

(setq meta-prefix-char -1)

So I tried it in GNU Emacs (very stale CVS checkout), and got a
segfault.  To reproduce it do:

emacs -q
(setq meta-prefix-char -1) C-x C-e
M-x

Apparently xemacs documents: "To disable the meta-prefix-char, set it
to a negative number."  Even if this usage is not legal in GNU Emacs,
trying it presumably should not cause a segfault.

It would be nice if it were possible to make the escape key a
non-prefix key (when running under a windowing system, not a console).

Peter