bug#23594: 25.0.94; Display errors on Linux tty

[Eli Zaretskii <eliz@gnu.org>]

> Date: Sat, 21 May 2016 10:47:20 +0000
> From: Alan Mackenzie <acm@muc.de>
> 
> emacs -Q
> C-x b foo.c
> M-x c-mode
> 
> Type the following five lines into the buffer:
> #########################################################################
> char foo [] = "foo";
> 
> #define FOO BAR
> 
> char bar [] = "bar";
> #########################################################################
> 
> Move point to just after "BAR" on line 3.
> C-u C-x =
> 
> There are now two display bugs evident:
> 1. The vertical divider between the two windows is missing a piece just
> after the line "  decomposition: (10) ('" in *Help*.
> 
> 2. In foo.c, the actual text display is out of sync with the text cursor.
> The text has been scrolled one line up, but the cursor has remained at
> the same position in the window, apparently at the end of a non-existent
> line of spaces.  The cursor can be freely moved, but is one line out of
> sync with the displayed text.

I see this, but I don't understand why you needed the c-mode stuff and
the text.  the same problem happens in a buffer in Fundamental mode
when you invoke "C-u C-x =" at a newline.

This bug exists since we started showing the 'decomposition' of
characters in Emacs 24.1.  With LF, we send a literal LF character to
the screen.