* lisp/man.el (Man-fit-to-window): Don't update on tty with MANWIDTH.

Check if 'Man-columns' is non-nil before trying to reformat
the manpage buffer.  The value of the varible 'Man-columns'
is nil on a non-window system where "MANWIDTH" or "COLUMNS"
is defined.  And the return value of the function 'Man-columns'
is meaningless in this case anyway.  So no need to react
to changes in window width (bug#74924).

lisp/man.el

@@ -1291,6 +1291,7 @@ Return the buffer in which the manpage will appear."
   (when (window-live-p window)
     (with-current-buffer (window-buffer window)
       (when (and (derived-mode-p 'Man-mode)
+                 Man-columns
                  (not (eq Man-columns (Man-columns))))
         (let ((proc (get-buffer-process (current-buffer))))
           (unless (and proc (not (eq (process-status proc) 'exit)))