+ * new feature: SB-EXT:ATOMIC-INCF allows atomic incrementation of
+ appropriately typed structure slots without locking.
+ * enhancement: reduced conservativism on GENCGC platforms: on
+ average 45% less pages pinned (measured from SBCL self build).
+ * bug fix: SB-EXT:COMPARE-AND-SWAP on SYMBOL-VALUE can no longer
+ mutate constant symbols or violate declaimed type of the symbol.
+