Use lazy-eval rather than actual-value for stored programs

We don't care about the actual value, because these are just defines,
so we only need their side effects.

mceval/leval.rkt

@@ -85,7 +85,7 @@
 (define (lazy-driver-loop)
   (define env (setup-environment))
   ;; Read in code to implement lazy lists
-  (eval-program lazy-lists-program actual-value user-print env)
+  (eval-program lazy-lists-program lazy-eval user-print env)
   (define (driver-loop)
     (prompt-for-input input-prompt)
     (let ((input (read)))
@@ -97,7 +97,7 @@
 
 (define (lazy-eval-program program)
   (define env (setup-environment))
-  (eval-program lazy-lists-program actual-value user-print env)
+  (eval-program lazy-lists-program lazy-eval user-print env)
   (eval-program program actual-value user-print env))
 
 ;;; Representing thunks