compctl -g broken in beta20

[Zefram <A.Main@xxxxxxxxxxxxxxxxx>]

The globbing changes in beta20 seem to have broken compctl -g
completions.  If the pattern is not matched, then it gets quoted and
used as if it matched:

% compctl -g 'foo*' foo
% foo <TAB>
% foo foo\*

This behaviour is dependent on NO_NOMATCH, NULL_GLOB and CSH_NULL_GLOB
(the former must be on and the others off).  Perhaps the neatest
solution is to temporarily turn on NULL_GLOB when doing the globbing,
as is already done in a couple of places?

-zefram