Provide a simple sample labeled access control policy, mac_partition.

This policy can be loaded dynamically, and assigns each process a
partition number, as well as permitting processes to operate outside
the partition.  Processes contained in a partition can only "see"
processes inside the same partition, so it's a little like jail.
The partition of a user can be set using the label mechanisms in
login.conf.  This sample policy is a good starting point for developers
wanting to learn about how to produce labeled policies, as it labels
only one kernel object, the process credential.

PR:
Submitted by:
Reviewed by:
Approved by:
Obtained from:	TrustedBSD Project
Sponsored by:	DARPA, Network Associates Laboratories

sys/modules/Makefile

@@ -68,6 +68,7 @@ SUBDIR=	3dfx \
 	mac_ifoff \
 	mac_mls \
 	mac_none \
+	mac_partition \
 	mac_seeotheruids \
 	mac_test \
 	mcd \