It turned out that Landlock Make hasn't been applying sandboxing for a
while, due to a mistyped if statement for `$(USE_SYSTEM_TOOLCHAIN)` it
should have had the opposite meaning. Regressions in the build configs
have been fixed. The rmrf() function works better now. The rm.com tool
works according to POSIX with the exception of supporting prompts.
After going through the MODE=dbg and MODE=zero build modes, a bunch of
little issues were identified, which have been addressed. Fixing those
issues created even more troubles for the project, because it improved
our ability to detect latent problems which are getting fixed so fast.
The organization of the source files is now much more rational.
Old experiments that didn't work out are now deleted. Naming of
things like files is now more intuitive.
