master f921f18 1/3: Partially revert previous make-separator-line change

[Lars Ingebrigtsen]

branch: master
commit f921f189ee3d77715247bc81a723c09408971cc4
Author: Lars Ingebrigtsen <larsi@gnus.org>
Commit: Lars Ingebrigtsen <larsi@gnus.org>

    Partially revert previous make-separator-line change
    
    * lisp/simple.el (make-separator-line): Use dashes on displays
    that don't support underlines (bug#32950).
---
 lisp/simple.el | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/lisp/simple.el b/lisp/simple.el
index 456844d..82e373b 100644
--- a/lisp/simple.el
+++ b/lisp/simple.el
@@ -721,10 +721,16 @@ When called from Lisp code, ARG may be a prefix string to 
copy."
 This uses the `separator-line' face.
 
 If LENGTH is nil, use the window width."
-  (if length
-      (concat (propertize (make-string length ?\s) 'face 'separator-line)
-              "\n")
-    (propertize "\n" 'face '(:inherit separator-line :extend t))))
+  (if (or (display-graphic-p)
+          (display-supports-face-attributes-p '(:underline t)))
+      (if length
+          (concat (propertize (make-string length ?\s) 'face 'separator-line)
+                  "\n")
+        (propertize "\n" 'face '(:inherit separator-line :extend t)))
+    ;; In terminals (that don't support underline), use a line of dashes.
+    (concat (propertize (make-string (or length (1- (window-width))) ?-)
+                        'face 'separator-line)
+            "\n")))
 
 (defun delete-indentation (&optional arg beg end)
   "Join this line to previous and fix up whitespace at join.