adapt to ${CC_WNO_ADDRESS_OF_PACKED_MEMBER}

Simplify CWARNFLAGS to use ${CC_WNO_ADDRESS_OF_PACKED_MEMBER}
which works for both clang and gcc, and remove compiler-specific
equivalents.

bsd.own.mk: rename to CC_WNO_ADDRESS_OF_PACKED_MEMBER

Provide a single variable
CC_WNO_ADDRESS_OF_PACKED_MEMBER
with options for both clang and gcc, to replace
CLANG_NO_ADDR_OF_PACKED_MEMBER
CC_NO_ADDR_OF_PACKED_MEMBER
GCC_NO_ADDR_OF_PACKED_MEMBER

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

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.

Disable a couple of warnings until further investigation.

branches: 1.6.2;
Put the kernelside rump kernel headers into <rump-sys> instead of
sprinkling them around the faction directories. Avoids having
to add a CPPFLAGS (or several) to pretty much every component
Makefile.

Leave compat headers around in the old locations.

The commit changes some autogenerated files, but I'll fix the
generators shortly and regen.

remove librump/rumpnet/opt, consolidate in rump/include/opt

branches: 1.4.20; 1.4.38;
Introduce RUMP_COMPONENT. It behaves mostly like a simplified
module which is linked into the kernel and cannot be unloaded.
The main purpose is to get the proper constructors run and create
any /dev nodes necessary for said component. Once more of the
kernel (e.g. networking stack and device drivers) are converted to
MODULE and devfs pops up from somewhere, rump components can be
retired.

branches: 1.3.2;
Add a dummyif, which doesn't actually traffic any cargo, but since
it has no backend it can always be attached and is therefore
convenient for testing ifconfig.

branches: 1.2.2; 1.2.4;
Purge multiple kernel opt files.

branches: 1.1.2; 1.1.4; 1.1.6; 1.1.8;
Add a very simplistic PF_INET/SOCK_DGRAM domain/proto implementation,
which delegates the work to host kernel sockets. This does not
run the entire kernel TCP/IP stack in userspace and therefore does
not require the ability to send or receive raw packets. This
implies that root priviledges are not required. As already said
above, only supports UDPv4 for now. Extending should be easy.