* bug fix: effective methods associated with a generic function are
no longer cached over a change of that generic function's method
combination. (reported by Andreas Fuchs)
+ * bug fix: RUN-PROGRAM now does not fail if some element in $PATH
+ names a non-existent directory. (thanks to Andreas Fuchs)
* optimization: restored some effective method precomputation in
CLOS (turned off by an ANSI fix in sbcl-0.8.3); the amount of
precomputation is now tunable.