MFC: r271864

Move rl(4) to dev/rl.

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

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

Make RL_TWISTER_ENABLE a tunable/sysctl. Eliminate it as an option.
Fix module build.

Submitted by: Kostik Belousov

Add RL_TWISTER_ENABLE option. This enables the magic bits to do long
cable tuning. This has helped in some installations for hardware
deployed by a former employer. Made optional because the lists aren't
full of complaints about these cards... even when they were wildly
popular.

Reviewed by: attilio@, jhb@, trhodes@ (all an older version of the patch)

Remove bridge(4) from the tree. if_bridge(4) is a full functional
replacement and has additional features which make it superior.

Discussed on: -arch
Reviewed by: thompsa
X-MFC-after: never (RELENG_6 as transition period)

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

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.

Zap KMODDEPS line

Add ${DEBUG_FLAGS} to CFLAGS in bsd.kmod.mk, not in scattered module
makefiles. Bad examples in fxp/Makefile keep getting copied to new
makefiles.

Removed special rules for building and cleaning device interface files
and empty options files. The rules are now generated automatically in
bsd.kmod.mk. Cleaned up related things ($S and ${CLEANFILES}).

Zap some unused echo "#define NFOO 1" > foo.h style defunct stuff.

Don't generate 'bpf.h' since it's not used.

Change the name of the installed KLM to contain a leading "if_".
Except for miibus which is now installed as miibus.ko.

Discussed by: msmith, peter, and wpaul

Convert the RealTek 8139 driver to newbus and miibus in one swell foop.
Also set it up to be compiled as a module.