Prefer AUE_FOO audit identifiers to AUE_O_FOO, which are largely left
over from the Darwin implementation.

When we implement a system call as a wrapper to sysctl(), audit it as
AUE_SYSCTL. This leads to greater compatibility with Solaris audit
trails as sysctl() argument tokens are not the same as the ones for
the originaly system calls (i.e., setdomainname()).

Replace references to AUE_ events that are equivilent to AUE_NULL with
AUE_NULL. In the case of process signal configuration, this is
because these events do not require auditing.

Move from the Darwin spelling of getsockopt() to the FreeBSD/Solaris
one.

Audit nmount().

Obtained from: TrustedBSD Project