This uses a precompiled lisp heap image, which cannot be generated
without already having another version of itself (not even another CL
implementation), so it's perfect breeding ground for a Thompson
hack. :-)

I've been told to wait for Ludovic's input on whether the package is
acceptable, due to the heap image issue, so postpone reviewing it if you
want.

Also, I assume there's no need to regenerate the heap image, unlike the
"lisp kernel" which is a C program and therefore needs to be compiled by
us to have its rpath and such fixed.