Index: /trunk/ccl/level-1/l1-streams.lisp
===================================================================
--- /trunk/ccl/level-1/l1-streams.lisp	(revision 4922)
+++ /trunk/ccl/level-1/l1-streams.lisp	(revision 4923)
@@ -1451,4 +1451,5 @@
 (make-built-in-class 'basic-input-stream 'basic-stream 'input-stream)
 (make-built-in-class 'basic-output-stream 'basic-stream 'input-stream)
+(make-built-in-class 'basic-io-stream 'basic-input-stream 'basic-output-stream)
 (make-built-in-class 'basic-character-input-stream 'basic-input-stream 'basic-character-stream 'character-input-stream)
 (make-built-in-class 'basic-character-output-stream 'basic-output-stream 'basic-character-stream 'character-output-stream)
@@ -1495,5 +1496,5 @@
 (defun allocate-basic-stream (class)
   (if (subtypep class 'basic-file-stream)
-    (gvector :basic-stream class 0 nil nil nil nil)
+    (gvector :basic-stream class 0 nil nil nil nil nil)
     (gvector :basic-stream class 0 nil nil)))