Splitting /rescue out of base.tgz

[Edgar Fuß <ef%math.uni-bonn.de@localhost>]

[Would this better belong to tech-install?]

I think it may make sense to split /rescue out of base.tgz into a separate set.
I just rendered a machine unusable during an update because, after having 
booted into the new kernel, extracting base.tgz failed (/ full), corrupting 
both bin/sbin and rescue. Tho only thing I had was a shell with whatever is 
built-in.
My colleague joked it was time to write a tar parser in shell (to extract 
/rescue from the base set to somewhere else), but unfortunately, base.tgz 
is compressed.
Note that it wouldn't suffice to duplicate /rescue into a separate tgz, 
it would need to be removed from base.tgz.
Of course, I could mimic this with args to tar xpzfC base.tgz /.