changes in sbcl-2.0.1 relative to sbcl-2.0.0:
* minor incompatible change: some symbols have been removed from *FEATURES*
based on a determination of which should be impermissible to examine
via #+ and #- reader macros in user-written code.
* optimization: DEFSTRUCT copiers including COPY-STRUCTURE are able to
stack-allocate the result when declared dynamic-extent.
* bug fix: loop analysis code more robust. In particular, loop nesting depth
is computed more accurately, improving the register allocation around
loops.