bump bebox and prep image sizes for GCC 9.

1. Remove all the special handling of variables (-d -p -P -s -S) that
were dealing with DBG (-d) LDSTATIC/NOPIE (-p), and the rest with
disabling/enabling sanitizers.
2. Use emalloc/estrdup for all the allocators instead of only some cases.
3. Add -V varspec which passes variables on the command line (as DBG
and LDSTATIC used to be passed before) instead of appending them
to the on-the-fly Makefile using -v varspec.
4. Change the distrib and rescue Makefiles to use -V instead of the removed
flags.

The motivation of this is to make variable handling consistent, less magical,
and remove the need for changing crunchgen each time we want to add disabling
an option by default.

(as proposed in tech-toolchain)

branches: 1.22.12;
+= for MAKEFS_FLAGS

branches: 1.21.6; 1.21.10;
Don't set -mmultiple or -mno-string for PowerPC, the difference is too
small to really matter and it sometimes even increases the size.

branches: 1.20.12; 1.20.24;
Remove terminfo.db as it's now embedded in libterminfo.

Use the rescue terminfo.db in our images instead of termcap.

Replace references to local and now no-longer-existing termcap files
with references to ${DISTRIBB}/common/termcap. Hi, abs@!

${NETBSDSRCDIR}/distrib/common/protocols => ${DISTRIBDIR}/common/protocols
${NETBSDSRCDIR}/distrib/common/services => ${DISTRIBDIR}/common/services

Use the generated protocols file. Save another 20k or so.

branches: 1.15.12; 1.15.14;
Since /etc/services has gotten rather large, use a minimal one for install
kernels. (mount_nfs is notably the only binary that doesn't gracefully deal
with the lack of an /etc/services file, it appears.)

Add support for the SMALL install image on prep

Make the ramdisk a little bigger

I changed the ramdisk size in the kernel, but failed to change the size
of the ramdisk image. Thanks to he for catching this one.

Add French, German and Polish sysinstmsgs to all ramdisks that include sysinst
expect those where at least one of the language variants isn't built,
and those that are known not to have enough space (i386 ramdisk-tiny).
Files added to list.sysinst, list.sysinst.en is used when these files
cannot be added.
This might hit a size limit on another build - but I have no (sane) way of
testing it.

branches: 1.10.4;
yet another distrib overhaul:
- move guts of distrib/Makefile.inc to distrib/common/Makefile.distrib
(fixes problem caused by implicit include of ../Makefile.inc in certain
submake conditions triggered by makefiles not yet in tree)
- removed mkdir of ${RELEASEDIR}/*; rely upon "snap_pre" target of
etc/Makefile to create all the release directories
- renamed RELINSTALL to RELEASE_INSTALL
- renamed FLOPPYINSTDIR to FLOPPY_RELEASEDIR
- renamed MDSETDIR to MDSET_RELEASEDIR
- removed ITARGET
- move release target from top level to appropriate subdirectory
- ensure release target has correct depends
- replace miniroot's IMAGE_MD_POST with common/Makefile.image IMAGEPOSTBUILD
- Makefile.image: add realall: ${IMAGE}

replace _SRC_TOP_ with NETBSDSRCDIR, since the latter is the "public" version

convert to new distrib world order.
xxx; untested

Use crunchgen -d flag to set DBG in the generated makefile.

- Be consistent how libhack is used: If extra HACKOBJS (e.g., gethost.o) are
required, define them before pulling in libhack/Makefile.inc so that the
dependencies work correctly.
- Other minor cleanups

Disable libhack's gethost.o (replacement gethostby{name,addr}()) by default,
as they only support reading /etc/hosts, and its the "least useful" of
the libhack routines. Add gethost.o back to Really Small media which
appears to need the space savings.

Fix cross-compile failure.

Add MTREE?= to add Makefiles and use when running mtree

Use symbol MTREECONF instead of MTREE to refer configuration file
to avoid conflicts. Pointed out by chs@netbsd.org.

Add prep installer