Revert "swapon: Do not overwrite Linux swap header"

This reverts commit cf04a7775a4e8ff6fd28c768be9daa3d83dd382e.This is
broken on armv7, and closer scrutiny of the reviews shows I was in error
when I thought it was ready.

swapon: Do not overwrite Linux swap header

Reviewed by: imp, jhb
Pull Request: https://github.com/freebsd/freebsd-src/pull/1084

sbin: Remove ancient SCCS tags.

Remove ancient SCCS tags from the tree, automated scripting, with two
minor fixup to keep things compiling. All the common forms in the tree
were removed with a perl script.

Sponsored by: Netflix

Remove $FreeBSD$: one-line sh pattern

Remove /^\s*#[#!]?\s*\$FreeBSD\$.*$\n/

Explicitly add more files to the 'runtime' package.

Sponsored by: The FreeBSD Foundation

Convert sbin/ to LIBADD
Reduce overlinking

Build swapon with WARNS=6.

Don't use a variable called stat, because it collides with stat(2).

A new jail(8) with a configuration file, to replace the work currently done
by /etc/rc.d/jail.

Create the altix project branch. The altix project will add support
for the SGI Altix 350 to FreeBSD/ia64. The hardware used for porting
is a two-module system, consisting of a base compute module and a
CPU expansion module. SGI's NUMAFlex architecture can be an excellent
platform to test CPU affinity and NUMA-aware features in FreeBSD.

Raise WARNS for various tools where possible.

Submitted by: Marius Nünnerich <marius@nuenneri.ch>

Switch the default WARNS level for sbin/ to 6.

Submitted by: Ulrich Spörlein

- Import the HEAD csup code which is the basis for the cvsmode work.

- Change the meaning of -h flag from giving the output in megabytes to
giving the output in a human-readable form. This behaviour is consistent
with most of system tools.
- Add -m and -g options to give output in megabytes and gigabytes
respectively.

Add 'swapctl' - as a hardlink to swapon/swapoff, and augment swapon with
swapctl functionality. The idea is to create a swapctl command that is
fairly close to the OpenBSD and NetBSD version. FreeBSD does not implement
swap priority (and it would be a mistake if we did) so we didn't bother with
that part of it.

Submitted by: Eirik Nygaard <eirikn@bluezone.no>
Augmented by: dillon (extensively)
Reviewed by: David Schultz <dschultz@uclink.Berkeley.EDU>

This is David Schultz's swapoff code which I am finally able to commit.
This should be considered highly experimental for the moment.

Submitted by: David Schultz <dschultz@uclink.Berkeley.EDU>
MFC after: 3 weeks

Default to WARNS=2.
Binary builds that cannot handle this must explicitly set WARNS=0.

Reviewed by: mike

Set WARNS=2 on programs which compile cleanly.

Submitted by: Mike Barcroft <mike@q9media.com>

- Backout botched attempt to introduce MANSECT feature.
- MAN[1-9] -> MAN.

Set the default manual section for sbin/ to 8.

Convert to our man installation style. Also fixed long-standing bug
in `fastboot'/`fasthalt' in which the interpreter would hang around
after `reboot' or `halt' is run, causing an irritating ``Killed'' message.

BSD 4.4 Lite sbin Sources

Note: XNSrouted and routed NOT imported here, they shall be imported with
usr.sbin.