lib: Remove ancient SCCS tags.

Remove ancient SCCS tags from the tree, automated scripting, with two
minor fixup to keep things compiling. All the common forms in the tree
were removed with a perl script.

Sponsored by: Netflix

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/

General further adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 3-Clause license.

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.

Special thanks to Wind River for providing access to "The Duke of
Highlander" tool: an older (2014) run over FreeBSD tree was useful as a
starting point.

Renumber copyright clause 4

Renumber cluase 4 to 3, per what everybody else did when BSD granted
them permission to remove clause 3. My insistance on keeping the same
numbering for legal reasons is too pedantic, so give up on that point.

Submitted by: Jan Schaumann <jschauma@stevens.edu>
Pull Request: https://github.com/freebsd/freebsd/pull/96

Revert r301707

getnetent_p doesn't return NULL like getnetent does. coccinelle got confused and
I didn't verify that it worked before committing the change

MFC after: 1 week
X-MFC with: r301707
Pointyhat to: ngie

Use NULL instead of `0` in _ht_getnetbyname(..)

- getnetent returns NULL on completion/error.
- .h_aliases is NULL terminated.

MFC after: 1 week
Sponsored by: EMC / Isilon Storage Division

libc: Make various internal file descriptors from fopen() close-on-exec.

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

- When there is no room for returning the result, nss backend
have to return ERANGE and terminate with NS_RETURN.
- When gethostbyname_r(3) and the friends end with an error,
set errno to the value nss backend returns, and return errno
value.

PR: kern/131623
MFC after: 2 weeks

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.

Per Regents of the University of Calfornia letter, remove advertising
clause.

# If I've done so improperly on a file, please let me know.

- make reentrant version of netdb functions glibc style API, and
expose them to outside of libc.
- make netdb functions NSS friendly.

Reviewed by: arch@ and current@ (no objection)

Update the resolver in libc to BIND9's one.

Since, res_sendsigned(3) and the friends use MD5 functions, it is
hard to include them without having MD5 functions in libc. So,
res_sendsigned(3) is not merged into libc.

Since, res_update(3) in BIND9 is not binary compatible with our
res_update(3), res_update(3) is leaved as is, except some
necessary modifications.
The res_update(3) and the friends are not essential part of the
resolver. They are not defined in resolv.h but defined in
res_update.h separately in BIND9. Further, they are not called from
our tree. So, I hide them from our resolv.h, but leave them only
for binary backward compatibility (perhaps, no one calls them).

Since, struct __res_state_ext is not exposed in BIND9, I hide it
from our resolv.h. And, global variable _res_ext is removed. It
breaks binary backward compatibility. But, since it is not used from
outside of our libc, I think it is safe.

Reviewed by: arch@ (no objection)

- Remove padding for ABI compatibility of n_net member from struct
netent.
- Change 1st argument of getnetbyaddr() to an uint32_t on 64 bit
arch as well to confirm to POSIX-2001.

These changes break ABI compatibility on 64 bit arch.
There is similar padding issue for ai_addrlen of struct addrinfo.
However, it is leaved as is for now.

Discussed on: arch@, standards@ and current@
X-MFC after: never

- The ai_addrlen of a struct addrinfo used to be a size_t, per
RFC 2553. In XNS5.2, and subsequently in POSIX-2001 and RFC
3493, it was changed to a socklen_t. And, the n_net of a
struct netent used to be an unsigned long integer. In XNS5,
and subsequently in POSIX-2001, it was changed to an uint32_t.
To accomodate for this while preserving ABI compatibility with
the old interface, we need to prepend or append 32 bits of
padding, depending on the (LP64) architecture's endianness.
- Correct 1st argument of getnetbyaddr() to uint32_t on 32
bit arch. Stay as is on 64 bit arch for ABI backward
compatibility for now.

Reviewed by: das, peter
MFC after: 2 weeks

NETDB_INTERNAL is not fit, here. return NO_RECOVERY for h_errno.

make getnetby*() thread-safe.

if last line didn't have trailing space, network address was also
treated as an alias.

Don't ignore the last line of config file (/etc/hosts, /etc/services, etc)
which doesn't end in \n, since it may be very confusing. Also this should
increase consistency, since most other config files work just fine regardless
of the presence of traling \n in the last line.

MFC After: 2 weeks

Fix the style of the SCM ID's.
I believe have made all of libc .c's as consistent as possible.

Remove 'register' keyword.

Add nsswitch support. By creating an /etc/nsswitch.conf file, you can
configure FreeBSD so that various databases such as passwd and group can be
looked up using flat files, NIS, or Hesiod.

= Hesiod has been added to libc (see hesiod(3)).

= A library routine for parsing nsswitch.conf and invoking callback
functions as specified has been added to libc (see nsdispatch(3)).

= The following C library functions have been modified to use nsdispatch:
. getgrent, getgrnam, getgrgid
. getpwent, getpwnam, getpwuid
. getusershell
. getaddrinfo
. gethostbyname, gethostbyname2, gethostbyaddr
. getnetbyname, getnetbyaddr
. getipnodebyname, getipnodebyaddr, getnodebyname, getnodebyaddr

= host.conf has been removed from src/etc. rc.network has been modified
to warn that host.conf is no longer used at boot time. In addition, if
there is a host.conf but no nsswitch.conf, the latter is created at boot
time from the former.

Obtained from: NetBSD

$Id$ -> $FreeBSD$

Merge in bind-4.9.6 resolver changes. Note that they resolve the
overflow problem differently.

Merge in bind-4.9.4-P1 resolver...

General -Wall warning cleanup, part I.
Submitted-By: Kent Vander Velden <graphix@iastate.edu>

The last of the bind-4.9.3-REL resolver merges.

Remove trailing whitespace.

get* rework and new bind code