many fixes for native GCC 12 builds

- default to dwarf4 since out ctf tools fail with dwarf5. i tried to
do this via subtarget options as other ports do, but this would
require adjusting several of the targets non-netbsd code, and ideally
we'll fix our tools sooner than later, so just hack it here for now.
- catch up config/rs6000/netbsd64.h (mostly delete things)
- remove some more upstream diffs in config/vax, though it does not work
currently - libc.so link fails due to weird relocations.
- include some headers to ensure types are available
- add missing sanitizer netbsd files to the 'dist' tree
- remove no longer present TIOCRCVFRAME and TIOCXMTFRAME interceptors
- expanding the sanitizer OS/cpu defs to cover more netbsd platforms
- copy across a few minor changes from gcc.old's sanitizer's (eg,
disabling linux-specific code, adding netbsd specific code.)
- add (untested, but building) tsan support for arm64
- re-enable the sanitzers, at least simple -fsanitize=address builds a
working application on amd64 now
- fix the source lists (mostly .cc -> .cpp rename here)
- add some missing new defines, -f*, and -W*
- bump sanitizer shlib version
- apply -fno-jump-tables in some more places on m68k
- update the list in README.gcc12 to note many things now work or a few
things to do not work (although there are many uncommited changes at
this point across the rest of 'src' and 'xsrc'.) main points are that
vax, hppa, ppc, and sh3 don't build yet, but most other things are
either testing and working or at least building.

Consistently, always link sanitizer runtime with libm and libpthread

This reflects the behavior from LLVM and avoids issues with dlsym(3) APIs.

Ignore unused private fields when building with clang

vaxinate sanitizer_file.cc against the optimizer virus.

- use /usr/include/gcc-8
- update sanitizer makefiles

also, reduce diffs to upstream:
- remove or1k support
- re-order various lines to match upstream
- move regex map code into file-prefix-map.[ch]

update the sanitizer source lists for gcc 7.

branches: 1.3.2;
vaxinate the sanitizer build.

branches: 1.2.2;
remove temp hack.

Add lsan support.

Consistently, always link sanitizer runtime with libm and libpthread

This reflects the behavior from LLVM and avoids issues with dlsym(3) APIs.

Ignore unused private fields when building with clang

vaxinate sanitizer_file.cc against the optimizer virus.

- use /usr/include/gcc-8
- update sanitizer makefiles

also, reduce diffs to upstream:
- remove or1k support
- re-order various lines to match upstream
- move regex map code into file-prefix-map.[ch]

update the sanitizer source lists for gcc 7.

branches: 1.3.2;
vaxinate the sanitizer build.

branches: 1.2.2;
remove temp hack.

Add lsan support.

Ignore unused private fields when building with clang

vaxinate sanitizer_file.cc against the optimizer virus.

- use /usr/include/gcc-8
- update sanitizer makefiles

also, reduce diffs to upstream:
- remove or1k support
- re-order various lines to match upstream
- move regex map code into file-prefix-map.[ch]

update the sanitizer source lists for gcc 7.

branches: 1.3.2;
vaxinate the sanitizer build.

branches: 1.2.2;
remove temp hack.

Add lsan support.

vaxinate sanitizer_file.cc against the optimizer virus.

- use /usr/include/gcc-8
- update sanitizer makefiles

also, reduce diffs to upstream:
- remove or1k support
- re-order various lines to match upstream
- move regex map code into file-prefix-map.[ch]

update the sanitizer source lists for gcc 7.

branches: 1.3.2;
vaxinate the sanitizer build.

branches: 1.2.2;
remove temp hack.

Add lsan support.

- use /usr/include/gcc-8
- update sanitizer makefiles

also, reduce diffs to upstream:
- remove or1k support
- re-order various lines to match upstream
- move regex map code into file-prefix-map.[ch]

update the sanitizer source lists for gcc 7.

branches: 1.3.2;
vaxinate the sanitizer build.

branches: 1.2.2;
remove temp hack.

Add lsan support.

update the sanitizer source lists for gcc 7.

branches: 1.3.2;
vaxinate the sanitizer build.

remove temp hack.

Add lsan support.

branches: 1.3.2;
vaxinate the sanitizer build.

remove temp hack.

Add lsan support.