bug#29430: 26.0.90; C-M-backspace is undefined

[Devon Sean McCullough]

> On Nov 24, 2017, at 2:28 PM, Noam Postavsky <npostavs@users.sourceforge.net> 
> wrote:
> Seems to be on purpose, bindings.el:1236:
> ;;; These are dangerous in various situations,
> ;;; so let's not encourage anyone to use them.
> ;;;(define-key global-map [C-M-delete] 'backward-kill-sexp)
> ;;;(define-key global-map [C-M-backspace] 'backward-kill-seep)

I doubt those historical reasons still hold
but let's be ultra-cautious — here's a minimal fix:

(unless (eq 'ns (window-system))
  ;; These were once dangerous in various situations,
  ;; so let's not encourage just anyone to use them.
  (define-key global-map [C-M-delete] 'backward-kill-sexp)
  (define-key global-map [C-M-backspace] 'backward-kill-sexp))

                Peace
                        --Devon

P.S. Microsoft apparently considered Ctrl+Alt+Del a security feature,
laughably assuming it would be difficult for malware to intercept it
and steal passwords with a fake login screen.

P.P.S. X11 had a misfeature where Ctrl+Alt+Del nuked all your work
which has been disabled by default for years now in most situations,
e.g.,
    
https://access.RedHat.com/documentation/en-us/red_hat_enterprise_linux/7/html/desktop_migration_and_administration_guide/enable-ctrl-alt-backspace
    
https://AskUbuntu.com/questions/367983/how-do-i-enable-ctrl-alt-backspace-to-kill-the-x-server

P.P.P.S. As much as I condemn the imperious cyber-satan at One Infinite Loop,
they set mostly legal and licensing booby traps, seldom technical ones.