Make Emacs stop asking “Active processes exist; kill them and exit anyway”

This snippet (goes into your .emacs customization file) will temporarily make Emacs believes that there is no active process when you kill it, and therefore you won’t get the annoying prompt.

(require 'cl-lib)
(defadvice save-buffers-kill-emacs (around no-query-kill-emacs activate)
  "Prevent annoying \"Active processes exist\" query when you quit Emacs."
  (cl-letf (((symbol-function #'process-list) (lambda ())))
    ad-do-it))