No devices on /usr -> mount -o nodev
No setuid programs in /var -> mount -o nodev,nosuid

Adding "noexec" in various places may cause too much damage
(e.g. for running DEINSTALL scripts from /var/db/pkg, configure
scripts, etc).

Inspired by OpenBSD's afterboot(8) manpage.

branches: 1.1.2;
Extract commonly used things like CDROMs, pseudo-filesystems (/proc, ...)
and mfs-based /tmp into their own files. Hint at them in the existing
files. (fstab needs an #include statement :)