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/

spdx: The BSD-2-Clause-FreeBSD identifier is obsolete, drop -FreeBSD

The SPDX folks have obsoleted the BSD-2-Clause-FreeBSD identifier. Catch
up to that fact and revert to their recommended match of BSD-2-Clause.

Discussed with: pfg
MFC After: 3 days
Sponsored by: Netflix

libc: further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using mis-identified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.

libc: do not include <sys/types.h> where <sys/param.h> was already included

According to style(9):
> normally, include <sys/types.h> OR <sys/param.h>, but not both.
(<sys/param.h> already includes <sys/types.h> when LOCORE is not defined).

Clean r268867.

Proposed by: bde

Use unsigned optlen in getsourcefilter()

Sizes can not be negative and the functions that use it
expect an unsigned value anyways.

Obtained from: Apple (Libc-997.90.3)
MFC after: 1 week

Use the LLINDEX macro to access the link-level I/F index. This makes
it possible to work with a different type for the sdl_index field --
it only requires a recompile.

Obtained from: Juniper Networks, Inc.

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.

Fix an obvious bug in getsourcefilter()'s use of struct __msfilterreq;
the kernel will return in msfr_nsrcs the number of source filters
in-mode for a given multicast group.
However, the filters themselves were never copied out, as the libc
function clobbers this field with zero, causing the kernel to assume
the provided vector of struct sockaddr_storage has zero length.
This bug would only affect users of SSM multicast, which is shimmed
in 7.x.
Picked up during mtest(8) refactoring.

MFC after: 1 day

Update copyright.

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

Fix missing prototype warnings. (Compile errors with -Werror on)
When using namespace.h/un-namespace.h, you use _ versions of syscalls.
Change getsockopt() to _getsockopt() and same for setsockopt().

Approved by: re

Fix a typo which crept in from an earlier version of this file.

Add missing userland support files from previous commit for the new
multicast source filter API functions.