config.el

;; 4 space tabs

(defun my-generate-tab-stops (&optional width max)
  "Return a sequence suitable for `tab-stop-list'."
  (let* ((max-column (or max 200))
		 (tab-width (or width tab-width))
		 (count (/ max-column tab-width)))
	(number-sequence tab-width (* tab-width count) tab-width)))

(setq default-tab-width 4)
(setq tab-width 4)
(setq tab-stop-list (my-generate-tab-stops))