Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

provide the absolute path for /etc/rc1

Upgrade the root partition mount to r/w before trying to write to it.

MFC after: 3 days

The probable boot device is "machdep.guessed_bootdev".

Further cleanup: remove useless entries from PATH, and be prepared
to use kern.bootdevname (if available) to identify the boot device
for updating the configuration. Fallback to /dev/fd0 as before.

Major cleanup of PicoBSD startup scripts, which now should be
closer to doing "the right thing".

The structure is now the following:

* /etc/rc (from MFS) loads the rest of /etc and /root from
/fd and then from floppy (if present), then transfers control
to /etc/rc1

* /etc/rc1 loads defaults from /etc/rc.conf.defaults, tries to
set the hostname basing on the MAC address of the first ethernet
interface, and then sources /etc/rc.conf and /etc/rc.conf.local
for local configurations

* The rest of the startup process is then performed (rc.network and so on).

Everything except the initial /etc/rc (from MFS) can be overridden with
a local version loaded from floppy. But in most cases, you should only need
to customize the following files in /etc:

rc.conf rc.firewall hosts

Previously there were a number of inconsistencies in the calling
between files, and also a lot of clutter in rc.conf and rc.firewall.
Also, "rc1" was called "rc" and would overwrite the initial /etc/rc
from MFS, making it really hard to figure out what was going on in
case of bugs.

Use /dev/fd0 instead of /dev/fd0c for mounting the floppy.
This must have to do with the use of devfs in -CURRENT, but i
have no idea when the devfs is actually mounted (is it a
side effect of mount -t nonfs or what ?) and when /dev/fd0c becomes
available.
For the time being, let's use this hack. Once I understand how devfs
works, this can be reverted back to the previous value, and also the
part of the build script which creates device entries can be nuked.
This is for -current only.

MF4S: Syncronise with Luigi's work in -stable.

The magic for autodetecting the boot media does not work anymore
on STABLE or CURRENT. Put the explicit name for the floppy.

remove rc and login.conf files prior to extraction of the new
rc and login.conf files from the /etc directory on the floppy.

This prevents the overwrite yes/no prompt from occuring in gzip.
(some PicoBSD disks use gzip and some use minigzip, so the gzip -f flag (force)
is not an option. minigzip has a different meaning for the -f flag.}

Move mfs-related files to a different subtree