bug#5923: 23.1.95; minibuffer-message discards input events

[Drew Adams]

> > Attached is the code I use for `C-u' in the minibuffer. I 
> > hope it helps.
> 
> It does.
> 
> But to tell you the truth the handling of this-command-keys and
> universal-argument prefix is much too delicate for me to 
> understand it, so I'm not surprised it doesn't work quite right
> if you mess with it in any non-trivial way.

Compare Emacs 22 (and earlier), where there is no bug.

The code was changed (C to Lisp, at least), and that introduced the regression.