The appropriate entry in /etc/group as returned by getgrnam() is
used to determine if 'su root' may be permitted, rather than
checking if membership exists in the result of getgroups().
The following changes were made regarding the behaviour of the special
group for 'su root'
* allow for definition of SUGROUP (defaults to "wheel") to override group name.
* use getgrnam(SUGROUP) instead of getgrgid(0).
* only scan getgrnam(SUGROUP)->gr_mem when checking for group membership.
* be more specific as to why 'su root' failed
NOTE: If a user's primary group is SUGROUP, and they're not a member
of SUGROUP in /etc/group, they will not be able to su.
Fix PR/2839: su will not build with Kerberos.
- Also:
-Don't coredump when $TERM is not set.
-Add prototypes, remove local old style declarations of system
functions.
-Recognize shells that contain "csh" as being csh alike.
-Don't build with SKEY unconditionally. Obey bsd.own.mk.
