+;;; 6 = sbcl-0.6.9, got rid of non-ANSI %DEFCONSTANT/%%DEFCONSTANT stuff
+;;; and deleted a slot from DEBUG-SOURCE structure.
+;;; 7 = around sbcl-0.6.9.8, merged SB-CONDITIONS package into SB-KERNEL
+;;; 8 = sbcl-0.6.10.4 revived Gray stream support, changing stream layouts