MFC r260039:

Turn off warnings about unused variables for a bunch of files under
contrib/ipfilter.

Copy head (r256279) to stable/10 as part of the 10.0-RELEASE cycle.

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

Update ipfilter 4.1.28 --> 5.1.2.

Approved by: glebius (mentor)
BSD Licensed by: Darren Reed <darrenr@reed.wattle.id.au> (author)

Disable several instances instances of clang's -Wself-assign warning.
All of these are harmless, and are in fact used to shut up warnings from
lint.

While here, remove -Wno-missing-prototypes from the xfs module
Makefile, as I could not reproduce those warnings either with gcc or
clang.

MFC after: 1 week

Reimplementation of world/kernel build options. For details, see:

http://lists.freebsd.org/pipermail/freebsd-current/2006-March/061725.html

The src.conf(5) manpage is to follow in a few days.

Brought to you by: imp, jhb, kris, phk, ru (all bugs are mine)

Let modules use the kernel's opt_*.h files if built along with
the kernel by wrapping all targets for fake opt_*.h files in
.if defined(KERNBUILDDIR). Thus, such fake files won't be
created at all if modules are built with the kernel.

Some modules undergo cleanup like removing unused or unneeded
options or .h files, without which they wouldn't build this way
or the other.

Reviewed by: ru
Tested by: no binary changes in modules built alone
Tested on: i386 sparc64 amd64

Fix standalone module build.

Reported by: Boris Samorodov <bsam@ipt.ru>

new files and compile defines to build new ipfilter

Don't define PFIL_HOOKS. It's no longer required in RELENG_5 or HEAD.

NOINET6 -> NO_INET6

Recognise NOINET6 as an indication to not build IPv6 enabled source even
if FreeBSD header files, etc, support it.

Submitted by: Sergey Mokryshev <mokr@mokr.net>

IPv6 is on by default in GENERIC so enable IPv6 in IPFilter too by default.

PR: kern/57730
Submitted by: FUKAUMI Naoki <fukaumi@soum.co.jp>

update to reflect PFIL_HOOKS api changes

Supported by: FreeBSD Foundation

Drop <bsd.man.mk> support from <bsd.kmod.mk>.

Not objected to by: -current

Relocate IPFilter from sys/netinet to sys/contrib/ipfilter.

Use a consistent style and one much closer to the rest of /usr/src

Fix typo

Back out opt_ipfilter.h creation I add recently and add -DIPFILTER=1
to CFLAGS instead
According to other sources, opt_ipfilter.h not supposed to be included for
modules

Fix prev. commit: NIPFILTER -> IPFILTER

Generate opt_ipfilter.h to fix 'make depend'

Use .include <bsd.kmod.mk> to get to ../../*/conf/kmod.mk instead of
encoding the relative path.

Pull in sys/conf/kmod.mk, rather than /usr/share/mk/bsd.kmod.mk.
This means that the kernel can be totally self contained now and is not
dependent on the last buildworld to update /usr/share/mk. This might
also make it easier to build 5.x kernels on 4.0 boxes etc, assuming
gensetdefs and config(8) are updated.

Add forgotten ip_fil.c and fil.c to kld version

Remove mlfk_ipl.c from here: no sources allowed in these directories!

Add ipfilter kld and wire it in.