PTRACE HARDENING: slight updates.
Merge apr-util 1.5.3 -> 1.5.4.  A minor bug fix update.
cxgbe/tom:  Catch up with r271119, syncache_add doesn't need tcbinfo lock.
Update comment (missed this bit in r272079).
Catch up with r271119.
Merge remote-tracking branch 'freebsd/master' into hardened/current/master
Merge remote-tracking branch 'freebsd/master' into hardened/current/hardening
Merge remote-tracking branch 'freebsd/master' into hardened/current/segvguard
Merge remote-tracking branch 'freebsd/master' into hardened/current/ptrace
Merge remote-tracking branch 'freebsd/master' into hardened/current/log
Merge remote-tracking branch 'freebsd/master' into hardened/current/userlandenhanced
Merge branch 'hardened/current/master' into hardened/current/unstable
Merge branch 'hardened/current/hardening' into hardened/current/unstable
Merge branch 'hardened/current/segvguard' into hardened/current/unstable
Merge branch 'hardened/current/ptrace' into hardened/current/unstable
Merge branch 'hardened/current/log' into hardened/current/unstable
Merge branch 'hardened/current/userlandenhanced' into hardened/current/unstable