anchor.diff:                      'nil
                       (sys.int::raise-bad-block ',(block-information-name tag)))
                     (return-from ,tag
  -                    (multiple-value-prog1 ,(lsb-form value-form)
  -                      (sys.int::%%unwind-to (sys.int::%%block-info-binding-stack-pointer ,info)))
  +                    ,(list
  +                      'multiple-value-prog1
  +                      (lsb-form value-form)
  +                      `(sys.int::%%unwind-to (sys.int::%%block-info-binding-stack-pointer ,info)))
                       ,info))))
             (t
              ;; Local RETURN-FROM, locate the matching BLOCK and emit any unwind forms required.
  
positive.code:       (when (not (lambda-information-p cleanup-function))
          ;; cleanup closures use the unwind-protect call protocol (code in r13, env in rbx, no closure indirection).
          (setf (getf (lambda-information-plist (second cleanup-function)) 'unwind-protect-cleanup) t))
        `(progn
           ,(cond
             ((lambda-information-p cleanup-function)
              `(sys.int::%%push-special-stack ,(lsb-form cleanup-function) '0))
             (t
              (setf (getf (lambda-information-plist (second cleanup-function)) 'unwind-protect-cleanup) t)
              `(sys.int::%%push-special-stack ,(lsb-form (second cleanup-function))
                                              ,(lsb-form (third cleanup-function)))))
           (multiple-value-prog1 ,(lsb-form protected-form)
             (sys.int::%%disestablish-unwind-protect))))))
  
negative.code:           (t ;; Non-local GO, do the full unwind.
             (let ((info (make-lexical-variable :name (gensym "go-info")
                                                :definition-point *current-lambda*)))
               `(let ((,info ,(lsb-form location)))
                  ;; Ensure it's still valid.
                  (if ,info
                      'nil
                      (sys.int::raise-bad-go-tag ',(go-tag-name tag)))
                  (sys.int::%%unwind-to (sys.int::%%tagbody-info-binding-stack-pointer ,info))
                  (go ,tag ,info)))))))
  
  (defun lsb-let (form)
    (let ((*special-bindings* *special-bindings*))
  