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: 1.3.12;
+= for MAKEFS_FLAGS

branches: 1.2.6; 1.2.10;
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: 1.1.12; 1.1.24;
Add ramdisk directory and files.

PR install/54780: in the (of course totally unlikely) case that sysinst
should crash, run "stty sane".

branches: 1.1.48; 1.1.50;
Add ramdisk directory and files.

more gnu directory removal.

branches: 1.2.30; 1.2.34;
Adjust file lists for recent move:
usr/sbin/chown -> sbin/chown
usr/bin/chgrp -> bin/chgrp

Add ramdisk directory and files.