bug#9496: 24.0.50; Segfault on TAB-only composition

[Eli Zaretskii]

> Date: Fri, 03 Feb 2012 23:18:50 -0800
> From: Paul Eggert <eggert@cs.ucla.edu>
> 
> On 02/03/2012 10:58 PM, Eli Zaretskii wrote:
> > Then don't do that.
> 
> I don't see why not.

Because the result is meaningless anyway.  Being able to "express" a
2G column wide "character" is not useful, so avoiding overflow for
that use case is not really a solution to the problem.

It would be a much better solution if char_width would limit the
result to the same sane limit we have in all the related functions and
macros, i.e. to 1000.  If you limit everything in that function to
1000, including its result, there's no danger of overflow anywhere,
and the resulting display is not too preposterous.