keyboard.c "version 1.724": Echo area handling is wrong after C-u

[Alan Mackenzie <acm@muc.de>]

Emacs 21.1 with a patched keyboard.c.  Linux tty.

My keyboard.c is that delivered with Emacs 21.1, patched with the diffs
between the 1.723 and 1.724 CVS versions.  [Apologies if the following
bug doesn't exist in an up-to-date Emacs 21.3 snapshot.  My slow modem
connection makes it difficult for me to check this out].

**************************************************

Note:  On a Linux tty, [esc ?[ ?C] is the sequence of events produced by
pressing the right-arrow key, and is converted to 'right by the
function-key-kap.

1: Type C-u and wait till it appears in the echo area.

2: Type <esc>.
"C-u ESC-" now appears in the echo area.

3: Type "[".
"C-u ESC [-" momentarily flickers in the echo area.  The two last
characters are instantly removed, leaving "C-u-".  THIS SHOULD NOT
HAPPEN.

4: Type "C"
"C-u right" now (correctly) appears in the echo area, and point has been
(correctly) advanced by four characters.

**************************************************

1: Bind [esc ?[ ?9] to some command, e.g. 'previous-line.  This
   key-sequence doesn't exist in function-key-map.

2: Repeat steps 1 to 4 above, except "9" rather than "C" should by typed.
The echo area is left with the wront contents "C-u 9", rather than the
correct "C-u ESC [ 9".  The command, together with the prefix argument,
is correctly executed.

**************************************************

1: Type M-3 and wait.
"ESC 3" appears in the echo area.

2: Type M-C-a.
"ESC 3 ESC C-a" flickers briefly in the echo area.  The echo area is then
instantly truncated to "ESC 3".  THIS SHOULD NOT HAPPEN.  Point is
correctly moved back by three defuns.  The echo area continues to show
(wrongly) "ESC 3" until the next keypress.

**************************************************

Cc's of subsequent emails would be appreciated.

Many thanks in advance.

-- 
Alan Mackenzie (Munich, Germany)
acm@muc.de