bug#16912: [PATCH] no longer use CSET for non-UTF8 locale in DFA engine

[Paul Eggert]

Thanks for looking into this.  Unfortunately the combination of the two 
patches causes "make check" to fail, because it reintroduces a titlecase 
bug.  I can draft a further patch for that, but in the meantime can you 
look at a few other things?

First, why does the first patch add those four using_utf8 calls to 
parse_bracket_exp?  Isn't that optimization valid regardless of whether 
the multibyte encoding is UTF-8?

Second, the comment "UTF-8 allows treating a simple, non-inverted MBCSET 
like a CSET." no longer seems to match the code, since addtok no longer 
invokes using_utf8.

Third, could you please draft a proper commit message?  The format is 
something like this:

grep: minor tuning for mb_case_map_apply

* src/kwsearch.c (mb_case_map_apply): Avoid unnecessary widening of
size_t to intmax_t.  Avoid unnecessary reinitialization of k.


That is, a first line of the form "program: short description".  Then an 
empty line.  Then a ChangeLog entry in standard GNU format.

I'll take a look at the second patch later.