Merge OpenBSM alpha 5 from OpenBSM vendor branch to head, both

Merge OpenBSM alpha 5 from OpenBSM vendor branch to head, both
contrib/openbsm (svn merge) and src/sys/{bsm,security/audit} (manual
merge).  Hook up bsm_domain.c and bsm_socket_type.c to the libbsm
build along with man pages, add audit_bsm_domain.c and
audit_bsm_socket_type.c to the kernel environment.

OpenBSM history for imported revisions below for reference.

MFC after:      1 month
Sponsored by:   Apple Inc.
Obtained from:  TrustedBSD Project

OpenBSM 1.1 alpha 5

- Stub libauditd(3) man page added.
- All BSM error number constants with BSM_ERRNO_.
- Interfaces to convert between local and BSM socket types and protocol
  families have been added: au_bsm_to_domain(3), au_bsm_to_socket_type(3),
  au_domain_to_bsm(3), and au_socket_type_to_bsm(3), along with definitions
  of constants in audit_domain.h and audit_socket_type.h.  This improves
  interoperability by converting local constant spaces, which vary by OS, to
  and from Solaris constants (where available) or OpenBSM constants for
  protocol domains not present in Solaris (a fair number).  These routines
  should be used when generating and interpreting extended socket tokens.
- Fix build warnings with full gcc warnings enabled on most supported
  platforms.
- Don't compile error strings into bsm_errno.c when building it in the kernel
  environment.
- When started by launchd, use the label com.apple.auditd rather than
  org.trustedbsd.auditd.