wildmat implementation updated in CURRENT

[Russ Allbery]

I've just replaced the wildmat code in CURRENT with a largely rewritten
version that assumes UTF-8 as the basic character set (but tries to also
handle local character sets if it can distinguish them from UTF-8, which
it normally can).  This is the version that we've been discussing in the
ietf-nntp list.  pureconv reports the associated test suite achieves 100%
code coverage, so while there may be bugs, there shouldn't be any glaring
ones.

With this commit, wildmat can now handle ! and , internally, and @ if the
appropriate interface is called.  This means that a bunch of NNTP commands
have just gained support for comma-separated patterns (and the meaning of
, has changed and now has to be escaped to match a literal comma, but most
people don't match against , so this shouldn't be a major problem).  It
also means that the support in most places for comma-separated patterns
can just be removed in favor of calling wildmat directly; I haven't done
this yet.

-- 
Russ Allbery (rra at stanford.edu)             <http://www.eyrie.org/~eagle/>