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

[Eli Zaretskii]

> From: Kenichi Handa <handa@gnu.org>
> Cc: juri@jurta.org, 13084@debbugs.gnu.org
> Date: Thu, 13 Dec 2012 22:39:29 +0900
> 
> I have not yet checked the code, but what I remember is that
> search_buffer checks the search string and decides which to
> use; boyer_moore or simple_search.  If all equivalent
> characters of all non-ASCII characters in the search string
> are in the same character group, we can use boyer_moore.

Yes, that's my reading of the code as well.

> Here, A and B belongs to the same character group iff A and
> B has the same multibyte sequence except for the last byte.
> In this condition, we should be able to use the table
> simple_translate.

OK, then maybe just the comments need to be fixed.  They shouldn't
talk about "charset" and "row", which are undefined in Unicode Emacs.
They should instead use terminology that correspond to UTF-8 multibyte
representation of characters we use today.