diff --git a/src/ikarus.boot b/src/ikarus.boot
index 0d8643d..1d7618f 100644
Binary files a/src/ikarus.boot and b/src/ikarus.boot differ
diff --git a/src/makefile.ss b/src/makefile.ss
index a609b2f..ba85bfb 100755
--- a/src/makefile.ss
+++ b/src/makefile.ss
@@ -80,6 +80,44 @@
   (define ikarus-system-primitives
     '(print-greeting))
 
+  (define library-legend
+    '([s   (ikarus system)]
+      [i   (ikarus)]
+      [r   (r6rs)]))
+
+  (define ikarus-library-map
+    '([define           s i r]
+      [define-syntax    s i r]
+      [module           s i  ]
+      [begin            s i r]
+      [set!             s i r]
+      [foreign-call     s i r]
+      [quote            s i r]
+      [syntax-case      s i r]
+      [syntax           s i r]
+      [lambda           s i r]
+      [case-lambda      s i r]
+      [type-descriptor  s i  ]
+      [letrec           s i r]
+      [if               s i r]
+      [when             s i r]
+      [unless           s i r]
+      [parameterize     s i  ]
+      [case             s i r]
+      [let-values       s i r]
+      [define-record    s i r]
+      [include          s i r]
+      [syntax-rules     s i r]
+      [quasiquote       s i r]
+      [with-syntax      s i r]
+      [let              s i r]
+      [let*             s i r]
+      [cond             s i r]
+      [and              s i r]
+      [or               s i r]
+      [print-greeting   s    ]
+      ))
+
   (define (make-collection)
     (let ([set '()])
       (case-lambda
@@ -87,6 +125,7 @@
         [(x) (set! set (cons x set))])))
 
   (define (make-system-data subst env)
+    (define who 'make-system-data)
     (let ([export-subst    (make-collection)] 
           [export-env      (make-collection)]
           [export-primlocs (make-collection)])
@@ -100,6 +139,8 @@
       (for-each
         (lambda (x)
           (cond
+            [(assq x (export-subst))
+             (error who "ambiguous export of ~s" x)]
             [(assq x subst) =>
              (lambda (p)
                (let ([label (cdr p)])
@@ -119,31 +160,52 @@
         ikarus-system-primitives)
       (values (export-subst) (export-env) (export-primlocs))))
 
+  (define (get-export-subset key subst)
+    (let f ([ls subst])
+      (cond
+        [(null? ls) '()]
+        [else
+         (let ([x (car ls)])
+           (let ([name (car x)])
+             (cond
+               [(assq name ikarus-library-map) =>
+                (lambda (q)
+                  (cond
+                    [(memq key (cdr q)) 
+                     (cons x (f (cdr ls)))]
+                    [else (f (cdr ls))]))]
+               [else 
+                ;;; not going to any library?
+                (f (cdr ls))])))])))
 
   (define (build-system-library export-subst export-env primlocs)
-    (let-values ([(code empty-subst empty-env)
-                  (boot-library-expand
-                    `(library (ikarus primlocs)
-                       (export) ;;; must be empty
-                       (import (scheme))
-                       (current-primitive-locations 
-                         (lambda (x) 
-                           (cond
-                             [(assq x ',primlocs) => cdr]
-                             [else #f])))
-                       (install-library 
-                          ',(gensym "system")   ;;; id
-                          '(system)             ;;; name
-                          '()                   ;;; version
-                          '()                   ;;; import libs 
-                          '()                   ;;; visit libs
-                          '()                   ;;; invoke libs
-                          ',export-subst        ;;; substitution
-                          ',export-env          ;;; environment
-                          void void             ;;; visit/invoke codes
-                          )))])
-       (pretty-print code)
-       code))
+    (define (build-library legend-entry)
+      (let ([key (car legend-entry)] [name (cadr legend-entry)]) 
+        (let ([id     (gensym)]
+              [name       name]
+              [version     '()]
+              [import-libs '()]
+              [visit-libs  '()]
+              [invoke-libs '()]
+              [subst (get-export-subset key export-subst)]
+              [env (if (equal? name '(ikarus system)) export-env '())])
+          `(install-library 
+             ',id ',name ',version ',import-libs ',visit-libs ',invoke-libs
+             ',subst ',env void void))))
+    (let ([code `(library (ikarus primlocs)
+                    (export) ;;; must be empty
+                    (import (scheme))
+                    (current-primitive-locations 
+                      (lambda (x) 
+                        (cond
+                          [(assq x ',primlocs) => cdr]
+                          [else #f])))
+                    ,@(map build-library library-legend))])
+      (parameterize ([print-gensym #f])
+        (pretty-print code))
+      (let-values ([(code empty-subst empty-env)
+                    (boot-library-expand code)])
+         code)))
 
   (define (expand-all files)
     (let ([code* '()]
@@ -159,6 +221,7 @@
                  (set! subst (append export-subst subst))
                  (set! env (append export-env env))))))
         files)
+      (printf "building system ...\n")
       (let-values ([(export-subst export-env export-locs)
                     (make-system-data subst env)])
         (let ([code (build-system-library export-subst export-env export-locs)])