the "maximum sane configuration" shouldn't have. (Explicit MTAB support in
mount, which you should only need if you have no /proc, and FEATURE_CLEAN_UP,
which exists to humor valgrind and otherwise just bloats the code).
symbol (switched on to remove now: test your apps to make sure they _don't_
do this, because as some point we should just yank it), fixup head/tail/fold.
Also tweak "make allyesconfig" so anything starting with CONFIG_DEBUG gets
left switched off. Possibly other things we want to put in the debug menu?
