MFC r326276:

various: general adoption of SPDX licensing ID tags.

Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified 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.

No functional change intended.

Copy head@r302406 to stable/11 as part of the 11.0-RELEASE cycle.
Prune svn:mergeinfo from the new branch, as nothing has been merged
here.

Additional commits post-branch will follow.

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

Add some missing #includes that weren't required due to namespace polution
in our headers.

Submitted by: bde

o Clean up some #includes
o Bump version number to 3.0.4
o When talking to a RADIUS server, provide a NAS-Port-Type.

When the NAS-Port-Type is Ethernet, provide a NAS-Port value equal
to the SESSIONID from the environment in direct mode or the
NGM_PPPOE_SESSIONID message in other modes. If no SESSIONID is found,
default to the interface index in client mode or zero in server mode.

When the NAS-Port-Type is ISDN, set the NAS-Port to the minor number
of the physical device (ie, the N in /dev/i4brbchN).

This makes it easier for the RADIUS server to identify the client
WRT accounting data etc.

Prompted by: lsz8425 <lsz8425@mail.cd.hn.cn>

Add some comments to explain what's going on here

$Id$ -> $FreeBSD$

Maintain a `necessary' marker to indicate that we *probably*
need to process a signal (usually a SIGALRM). Check to see
if we need to process a signal both before *and* after calling
select() as older (pre-2.0) versions of ppp used to.

This handles the possibility that ppp may block at some
point (maybe due to an open() of a misconfigured device).
Previously, we'd potentially lock up in select().

The `necessary' marker reduces the increased signal checking
overhead so that at full speed with no compression transferring
an 83Mb file via a ``!ppp -direct'' device, we get a 1%
throughput gain.

MFMP: Make ppp multilink capable.
See the file README.changes, and re-read the man page.

Explicitly call `caused' an `int'.
Sugested by: gcc-2.8

Add (BSD) copyright headers.

Fix prototypes.
Remove extraneous decls.
Add ``const'' to several places.
Allow ``make NOALIAS=1'' to remove IP aliasing.
Merge with OpenBSD - only the Makefiles vary.

We can now survive a compile with
-Wall -Wbad-function-cast -Wcast-align -Wcast-qual
-Winline -Wmissing-declarations -Wmissing-prototypes
-Wnested-externs -Wpointer-arith -Wredundant-decls
-Wshadow -Wstrict-prototypes -Wwrite-strings -Wchar-subscripts
(although the Makefile just contains -Wall).

Cosmetic (no functional changes):
o Add missing $Id$s
o Move extern decls from .c -> .h files
o Staticize
o Remove #includes from .h files
o style(9)ify includes
o bcopy -> memcpy
bzero -> memset
bcmp -> memcmp
index -> strchr
rindex -> strrchr
o Move timeout.h -> timer.h (making it consistent w/ timer.c)
o Add -Wmissing-prototypes

Make the code format more in line with style(9).
Update loadalias to use the new libalias api.
Update to version 1.1.

Overhaul ppp:
o Use syslog
o Remove references to stdout/stderr (incl perror())
o Introduce VarTerm - the interactive terminal or zero
o Allow "set timeout" to affect current session
o Change "set debug" to "set log"
o Allow "set log [+|-]flag"
o Make MSEXT and PASSWDAUTH stuff the default
o Move all #ifdef DEBUG stuff into the code - this
shouldn't be too much overhead. It's now controlled
with "set log +debug"
o Add "set log command, debug, tun, warn, error, alert"
o Remove cdefs.h, and assume an ansi compiler.
o Improve all diagnostic output
o Don't trap SIGSEGV
o SIGHUP now terminates again (log files are controlled
by syslog)
o Call CloseModem() when changing devices
o Fix parsing of third arg of "delete"

I think this fixes the "magic is same" problems that some
people have been experiencing.
The man page is being rewritten. It'll follow soon.

Reviewed by: ache@freebsd.org
These changes should fix the signal "problems" in ppp.
The signal changes should really be put into 2.2 too !
The following patches should do it. There were some other
changes made by Andrey recently that havn't been brought
into 2.2, it may be worth doing them now.