Fix a few packages to work with nil tab-stop-list

* indent.el (indent-accumulate-tab-stops): New function.

* textmodes/picture.el (picture-set-tab-stops):
* ruler-mode.el (ruler-mode-mouse-add-tab-stop)
(ruler-mode-ruler): Fix to work with nil tab-stop-list.

* progmodes/asm-mode.el (asm-calculate-indentation): Use
indent-next-tab-stop.

1 files changed, 2 insertions, 1 deletions

diff --git a/lisp/textmodes/picture.el b/lisp/textmodes/picture.el
index b11b773dee1..94d02bebb6a 100644
--- a/lisp/textmodes/picture.el
+++ b/lisp/textmodes/picture.el
@@ -418,7 +418,8 @@ stops computed are displayed in the minibuffer with `:' at each stop."
   (save-excursion
     (let (tabs)
       (if arg
-          (setq tabs (default-value 'tab-stop-list))
+          (setq tabs (or (default-value 'tab-stop-list)
+                         (indent-accumulate-tab-stops (window-width))))
         (let ((regexp (concat "[ \t]+[" (regexp-quote picture-tab-chars) "]")))
           (beginning-of-line)
           (let ((bol (point)))