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.

Uses LFS boot code

branches: 1.17.40;
Add empty LIBCRTI= as LIBCRT0 to build sa programs without installed DESTDIR.

XXX: probabry we should have bsd.saprog.mk or something.

branches: 1.16.112; 1.16.122; 1.16.128;
merge ktrace-lwp.

Define LIB{CRT0,C,CRTBEGIN,CRTEND} as nothing, we don't need to link
against them.

branches: 1.14.10;
Convert `bootxx' to raw binary format which is what the MI installboot(8)
program needs.

branches: 1.13.8; 1.13.12;
bootxx links at 0x340000
2nd-stage boot programs choices: 0x200000,0x300000,0x400000,0x700000 (default: 0x300000)

RELOC -> RELOC_DEFAULT

branches: 1.11.2;
Use ${SIZE}, ${OBJCOPY} rather than size and objcopy.

Add -DLIBSA_NO_CLOSE

branches: 1.9.2; 1.9.4;
Use `-Ttext' switch & collect ld options in LINKFLAGS.

Completely rearrange SPARC boot code, modeling it after alpha and hp300
ports' boot programs. Also added support for loading gzip'd kernels,
useful for booting from floppy. From Jason R. Thorpe <thorpej@nas.nasa.gov>,
tested by Matthew Green <mrg@eterna.com.au> and Erik Fair <fair@clock.org>.

STRIP -> STRIPFLAG

remove header munging hack.

We don't need `rem.o'.

branches: 1.4.2;
Brr.. libkern.o is way too big for our bootxx..

Make this work with OBJ dirs.

Don't strip bootxx on installation.

Network booting; "oldmon" support; combine all functionality in single images.
Many thanks to Gordon Ross and Chuck Cranor for figuring out and testing
the old monitor (sun4) stuff.