libc: Purge unneeded cdefs.h

These sys/cdefs.h are not needed. Purge them. They are mostly left-over
from the $FreeBSD$ removal. A few in libc are still required for macros
that cdefs.h defines. Keep those.

Sponsored by: Netflix
Differential Revision: https://reviews.freebsd.org/D42385

Remove $FreeBSD$: one-line .c pattern

Remove /^[\s*]*__FBSDID\("\$FreeBSD\$"\);?\s*\n/

Use the __DECONST macro rather than hand rolling the same thing.

Sponsored by: DARPA, AFRL

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.

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

- Remove the lsearch() and lfind() functions and their manpage from
the compatibility library libcompat.
- Add new implementations of lsearch() and lfind() which conform to
IEEE Std 1003.1-2001 to libc. Add a new manual page for them and
add them to the makefile.
- Add function prototypes for lsearch() and lfind() to the search.h
header.