> sys/ucred.h has a structure with NGROUPS used within it. 
> This is defined, via sys/param.h and sys/syslimits.h.
> 
> Are they supposed to be included, by mount.h where it includes
> sys/ucred.h at the top?

IMHO sys/param.h should be included by sys/ucred.h, because that's
where NGROUPS is used. Many packages that I tried to compile don't
compile because of this (they include sys/mount.h which in turn
includes sys/ucred.h which uses NGROUPS, but NGROUPS is not defined
because sys/param.h was not included). I think I had this problem
when I tried to compile CNews.

Blaz