bug#9172: 24.0.50; describe-char fails for combining character when on xterm

[Eli Zaretskii]

> Date: Tue, 26 Jul 2011 08:44:51 +0200
> From: Ulrich Mueller <ulm@gentoo.org>
> 
> With Emacs started on an xterm, function describe-char fails when a
> combining character is at point.
> 
> Steps to reproduce:
> $ emacs -Q -nw
> a C-x 8 RET combining diaeresis RET C-b C-u C-x =
> 
> Actual result:
> Error message "Wrong type argument: sequencep, 38"

FWIW, I cannot reproduce this (also on an x86_64 GNU/Linux system),
neither in Emacs 23 nor with today's trunk.  In fact,
internal-char-font doesn't even get called here with this recipe.  I
guess this has something to do with local system differences, and
perhaps with configure-time options.

Hopefully, the backtrace will allow to solve this nonetheless.