(mode_line_string): Support MS-DOS frames.

src/ChangeLog

@@ -1,3 +1,7 @@
+1999-12-29  Eli Zaretskii  <eliz@is.elta.co.il>
+
+	* dispnew.c (mode_line_string): Support MS-DOS frames.
+
 1999-12-29  Gerd Moellmann  <gerd@gnu.org>
 
 	* eval.c (syms_of_eval): Initialize debugger_may_continue.

src/dispnew.c

@@ -5152,8 +5152,8 @@ mode_line_string (w, x, y, mode_line_p, charpos)
   int x0;
   Lisp_Object string = Qnil;
 
-  /* Only do this for frames under a window system.  */
-  if (!FRAME_WINDOW_P (f))
+  /* Only do this for frames under a window system and MS-DOS frames.  */
+  if (!FRAME_WINDOW_P (f) && !FRAME_MSDOS_P (f))
     return Qnil;
 
   if (mode_line_p)