bug#13084: boyer_moore crashes with certain characters in the case table

[Eli Zaretskii <eliz@gnu.org>]

> From: Juri Linkov <juri@jurta.org>
> Date: Wed, 05 Dec 2012 02:34:39 +0200
> 
> The minimal reproducible recipe for crashes in boyer_moore noticed in bug#13041:
> 
> 1. emacs -Q
> 
> 2. Eval in *scratch*:
> 
> (let ((table (standard-case-table)) canon)
>   (setq canon (copy-sequence table))
>   (aset canon #xff59 ?y)
>   (set-char-table-extra-slot table 1 canon)
>   (set-char-table-extra-slot table 2 nil)
>   (set-standard-case-table table))
> 
> 3. Start an activity that includes a search, e.g. `C-x 8 RET TAB'

Thanks.  I think i fixed this (revision 111021 on the emacs-24
branch), please test.

In addition, I'd suggest that Handa-san (or someone else) takes a good
look at the code that sets up the simple_translate table in
boyer_moore, because the constants there, like 0200 and 0x3F, and all
the talk about characters that belong "to the same charset and row"
smell of pre-Unicode (a.k.a. "MULE") representation of characters.
For now, I disabled boyer_moore for unibyte characters beyond 160,
because my reading of the code is that simple_translate and the
supporting code cannot handle that.  Maybe I'm wrong.