Add support for netmap in GENERIC by default.
Avoid installing security.functions with executable bits, periodic(8) will
try to execute all files with an executable bit in /etc/periodic/*/ while
this file is supposed only to be sourced by others

MFC after:	1 week
Merge remote-tracking branch 'freebsd/master' into hardened/current/master
Merge remote-tracking branch 'origin/hardened/current/master' into hardened/current/ptrace