of allocating what ever the user asks for up to "ngroups_max + 1". On
systems with large values of kern.ngroups this will be more efficient.
The now redundant check that the array is large enough in
kern_getgroups() is deliberate to allow this change to be merged to
stable/8 without breaking potential third party consumers of the API.
Reported by: bde
MFC after: 28 days
c67fa34ee5