Rename MOUNTCRITLOCAL to CRITLOCALMOUNTED to avoid a name collision
on case insensitive file systems

Split the local disk availability step into two phases to allow scripts
that pre-populate parts of the system (e.g. a tmpfs based /var) an
easy place to plug in like:

# REQUIRE: mountcritlocal
# BEFORE: MOUNTCRITLOCAL

This also cleans up the existing special handling a bit by separating it
into new scripts. All later scripts now depend on MOUNTCRITLOCAL.
Discussed on tech-userlevel some time ago.

'file system' for consistency with documentation (instead of 'filesystem').

branches: 1.8.56; 1.8.70;
Add an _rc_subr_loaded variable, set to ":" by rc.subr. Scripts can use this
for a speedup by doing:
$_rc_subr_loaded . /etc/rc.subr

don't bother warning or supporting obsolete $critical_filesystems_beforenet
or $critical_filesystems; postinstall now checks for these

Replace $critical_filesystems_beforenet with $critical_filesystems_local .
Replace $critical_filesystems with $critical_filesystems_remote .

The new names are now consistent with the type argument that
mount_critical_filesystems() is called with, and allows for other types to
be easily supported by that function.

For backwards compatibility purposes, if the now obsolete variable is defined
(even empty), it takes precedence over the new form, and you will be warned.
If you want to stop the warnings, update your rc.conf(5) settings!

Rename NETWORK to NETWORKING, to allow rc.d to be on a case insensitive
file system (prevents conflict with 'network'). PROVIDE both NETWORKING
and NETWORK (the latter for compatibility with 3rd party scripts).

clarify purposes

* add new dummy dependancy `NETWORK' to be REQUIREd by services which need
networking to be operational before starting, and use as appropriate.
NETWORK depends upon network and dhclient.
* move the guts of systemfs into mountcritlocal
* replace the dependancy on systemfs with mountcritremote, and remove the
former.
* SERVERS now also depends upon ppp

Notes:
* dhclient (and others) needs /var to be a $critical_filesystem_beforenet
* dhclient now starts before syslogd (because the latter needs /usr, and
/usr might need dhclient to be mounted)

Should fix PRs:
[install/9853] [bin/10002] [misc/10349] [port-i386/10633] [misc/10641]

branches: 1.2.4;
Use load_rc_config() (from rc.subr) instead of sourcing /etc/rc.conf.
This allows us or a user to change the configuration file method in
one place - rc.subr - without having to edit all of the rc.d/* files.

branches: 1.1.1;
Initial revision