bsd.own.mk: rename GCC_NO_* to CC_WNO_*

Rename compiler-warning-disable variables from
GCC_NO_warning
to
CC_WNO_warning
where warning is the full warning name as used by the compiler.

GCC_NO_IMPLICIT_FALLTHRU is CC_WNO_IMPLICIT_FALLTHROUGH

Using the convention CC_compilerflag, where compilerflag
is based on the full compiler flag name.

rtadvd: no longer need packed member warning

add support for new GCC 9 warnings that may be too much to fix
right now. new address-of-packed-member and format-overflow
warnings have new GCC_NO_ADDR_OF_PACKED_MEMBER amd
GCC_NO_FORMAT_OVERFLOW variables to remove these warnings.

apply to a bunch of the tree. mostly, these are real bugs that
should be fixed, but in many cases, only by removing the 'packed'
attribute from some structure that doesn't really need it. (i
looked at many different ones, and while perhaps 60-80% were
already properly aligned, it wasn't clear to me that the uses
were always coming from sane data vs network alignment, so it
doesn't seem safe to remove packed without careful research for
each affect struct.) clang already warned (and was not erroring)
for many of these cases, but gcc picked up dozens more.

rtadvd: Remove router renumbering - it's been disable for years

introduce some common variables for use in GCC warning disables:

GCC_NO_FORMAT_TRUNCATION -Wno-format-truncation (GCC 7/8)
GCC_NO_STRINGOP_TRUNCATION -Wno-stringop-truncation (GCC 8)
GCC_NO_STRINGOP_OVERFLOW -Wno-stringop-overflow (GCC 8)
GCC_NO_CAST_FUNCTION_TYPE -Wno-cast-function-type (GCC 8)

use these to turn off warnings for most GCC-8 complaints. many
of these are false positives, most of the real bugs are already
commited, or are yet to come.


we plan to introduce versions of (some?) of these that use the
"-Wno-error=" form, which still displays the warnings but does
not make it an error, and all of the above will be re-considered
as either being "fix me" (warning still displayed) or "warning
is wrong."

use expandm from libwrap.

branches: 1.21.2; 1.21.4;
use librumpres

Disable a couple of warnings until further investigation.

branches: 1.19.2;
No more obvious strict aliasing violations here.

Introduce rump.rtadvd

It is used to write ATF tests for RA.

From s-yamaguchi@IIJ.

Remove many HAVE_GCC || HAVE_PCC conditionals as the options also apply
to Clang. Add a few cases of HAVE_LLVM for -fno-strict-aliasing.

Add RDNSS and DNSSL support, RFC6106.
Replace custom lists with TAILQ lists.
Clean up plently of signed vs unsigned warnings and set WARNS=4.

Adapted from FreeBSD.

branches: 1.15.2;
remove most of the remaining HAVE_GCC tests that are always true in
the modern world.

branches: 1.14.4;
add -DROUTEINFO

Enable WARNS=4 by default, except for:
cpuctl dumplfs hprop ipf iprop-log kadmin kcm kdc kdigest
kimpersonate kstash ktutil makefs ndbootd ntp pppd quot
racoon racoonctl rtadvd sntp sup tcpdchk tcpdmatch tcpdump
traceroute traceroute6 user veriexecgen wsmoused zic
(Mostly third-party applications)

branches: 1.12.6;
Wrap compiler-specific flags with HAVE_GCC and HAVE_PCC as necessary. Add a few flags for PCC.

branches: 1.11.12;
Add new Makefile knob, USE_FORT, which extends USE_SSP by turning on the
FORTIFY_SOURCE feature of libssp, thus checking the size of arguments to
various string and memory copy and set functions (as well as a few system
calls and other miscellany) where known at function entry. RedHat has
evidently built all "core system packages" with this option for some time.

This option should be used at the top of Makefiles (or Makefile.inc where
this is used for subdirectories) but after any setting of LIB.

This is only useful for userland code, and cannot be used in libc or in
any code which includes the libc internals, because it overrides certain
libc functions with macros. Some effort has been made to make USE_FORT=yes
work correctly for a full-system build by having the bsd.sys.mk logic
disable the feature where it should not be used (libc, libssp iteself,
the kernel) but no attempt has been made to build the entire system with
USE_FORT and doing so will doubtless expose numerous bugs and misfeatures.

Adjust the system build so that all programs and libraries that are setuid,
directly handle network data (including serial comm data), perform
authentication, or appear likely to have (or have a history of having)
data-driven bugs (e.g. file(1)) are built with USE_FORT=yes by default,
with the exception of libc, which cannot use USE_FORT and thus uses
only USE_SSP by default. Tested on i386 with no ill results; USE_FORT=no
per-directory or in a system build will disable if desired.

u_char -> char for several things:
- inet_ntop()
- if_indextoname()
- variable assignment matching
char -> u_char in one place for variable assignment matching

use -fno-strict-aliasing for dump.c with GCC4

libcompat isn't needed any more here.

use pidfile(3). sync w/kame

Need <bsd.own.mk> now.

Don't install the example config if MKSHARE=no.

make it clearer that /etc/rtadvd.conf is optional (normally,
configurations were derived from kernel interface settings).

install rtadvd.conf into /usr/share/exapmles/rtadvd, instead of /etc.

sync with kame.

sync with latest kame.
- decrease warning level on missing rtadvd.conf (actually, the file
can be omitted)
- strict prototype
- gather stats better, emit stats on SIGUSR1 to /var/run

s/CFLAGS/CPPFLAGS/ for -D and -I.

rtadvd: advertise IPv6 prefix info via router advertisement.
(to be run on routers)