sys: Remove $FreeBSD$: one-line sh pattern

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

Fix some modules to export more used symbols

and remove non-present symbols that are now reported by kmod_syms.awk.

Reviewed by: emaste
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D32878

Move most of the contents of opt_compat.h to opt_global.h.

opt_compat.h is mentioned in nearly 180 files. In-progress network
driver compabibility improvements may add over 100 more so this is
closer to "just about everywhere" than "only some files" per the
guidance in sys/conf/options.

Keep COMPAT_LINUX32 in opt_compat.h as it is confined to a subset of
sys/compat/linux/*.c. A fake _COMPAT_LINUX option ensure opt_compat.h
is created on all architectures.

Move COMPAT_LINUXKPI to opt_dontuse.h as it is only used to control the
set of compiled files.

Reviewed by: kib, cem, jhb, jtl
Sponsored by: DARPA, AFRL
Differential Revision: https://reviews.freebsd.org/D14941

sys/modules: normalize .CURDIR-relative paths to SRCTOP

This simplifies make output/logic

Tested with: `cd sys/modules; make ALL_MODULES=` on amd64
MFC after: 1 month
Sponsored by: Dell EMC Isilon

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

Add opt_compat.h to SRCS.

Remove opt_mac.h generation for various kernel modules that no longer
require it.

Submitted by: pjd

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

Fix the standalone module build.

Zap some bad examples:
opt_foo.h:
touch opt_foo.h
.. is unnecessary - kmod.mk does this for us.

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

sysvipc loadable.

new syscall entry lkmressys - "reserved loadable syscall"

Make syscall_register allow overwriting of such entries (lkmressys).