* lisp/international/mule-util.el (truncate-string-ellipsis): New var.

(truncate-string-to-width): Use it.

etc/NEWS

@@ -46,6 +46,8 @@ Use './configure PKG_CONFIG=/full/name/of/pkg-config' if you need to.
 
 * Changes in Emacs 24.5
 
+** New var `truncate-string-ellipsis' to choose how to indicate truncation.
+
 ---
 ** The default value of `history-length' has increased to 100.
 

lisp/ChangeLog

+2014-06-19  Stefan Monnier  <monnier@iro.umontreal.ca>
+
+	* international/mule-util.el (truncate-string-ellipsis): New var.
+	(truncate-string-to-width): Use it.
+
 2014-06-19  Robert Brown  <robert.brown@gmail.com>  (tiny change)
 	* emacs-lisp/lisp-mode.el (lisp-string-after-doc-keyword-p): New fun.

lisp/international/mule-util.el

@@ -56,6 +56,9 @@
 	(setq i (1+ i)))))
   string)
 
+(defvar truncate-string-ellipsis "..."  ;"…"
+  "String to use to indicate truncation.")
+
 ;;;###autoload
 (defun truncate-string-to-width (str end-column
 				     &optional start-column padding ellipsis)
@@ -80,11 +83,11 @@ If ELLIPSIS is non-nil, it should be a string which will replace the
 end of STR (including any padding) if it extends beyond END-COLUMN,
 unless the display width of STR is equal to or less than the display
 width of ELLIPSIS.  If it is non-nil and not a string, then ELLIPSIS
-defaults to \"...\"."
+defaults to `truncate-string-ellipsis'."
   (or start-column
       (setq start-column 0))
   (when (and ellipsis (not (stringp ellipsis)))
-    (setq ellipsis "..."))
+    (setq ellipsis truncate-string-ellipsis))
   (let ((str-len (length str))
 	(str-width (string-width str))
 	(ellipsis-len (if ellipsis (length ellipsis) 0))