+ * bug fix: RESTART-FRAME and RETURN-FROM-FRAME stack corruption
+ * bug fix: the discriminating function for PRINT-OBJECT no longer preserves
+ potentially-invalid effective methods in its cache.
+ * improvement: on x86/x86-64 Lisp call frames now have the same layout as C
+ frames, allowing for instance more reliable backtraces.
+ * optimization: faster local calls on x86/x86-64
+ * minor incompatible changes: echo-streams now propagate unread-char to the
+ underlying input stream, and no longer permit unreading more than one
+ character.
+ * improvement: the debugger REPL can now reference lexical variables
+ by name directly for code compiled with (DEBUG 3).