diff --git a/compiler/alpha/c-call.lisp b/compiler/alpha/c-call.lisp
index fffe13bae6a21c65e38d4721a73cc746a2891cea..d0df30a4315527a94b903b2d3b6fd577a279d71a 100644
--- a/compiler/alpha/c-call.lisp
+++ b/compiler/alpha/c-call.lisp
@@ -5,7 +5,7 @@
 ;;; Carnegie Mellon University, and has been placed in the public domain.
 ;;;
 (ext:file-comment
-  "$Header: /Volumes/share2/src/cmucl/cvs2git/cvsroot/src/compiler/alpha/c-call.lisp,v 1.2 1994/10/31 04:39:51 ram Exp $")
+  "$Header: /Volumes/share2/src/cmucl/cvs2git/cvsroot/src/compiler/alpha/c-call.lisp,v 1.3 2003/07/20 13:53:11 emarsden Rel $")
 ;;;
 ;;; **********************************************************************
 ;;;
@@ -176,3 +176,16 @@
 	      (t
 	       (inst li delta temp)
 	       (inst addq nsp-tn temp nsp-tn)))))))
+
+
+;; bogus stubs for now
+
+(export '(make-callback-trampoline callback-accessor-form))
+
+(defun callback-accessor-form (type sp offset)
+  (error "Callbacks not implemented on Alpha"))
+
+(defun make-callback-trampoline (index return-type)
+  "Cons up a piece of code which calls call-callback with INDEX and a
+pointer to the arguments."
+  (error "Callbacks not implemented on Alpha"))
diff --git a/compiler/ppc/c-call.lisp b/compiler/ppc/c-call.lisp
index 76dbae41e2ef776f96c8d378b953e6e2dd31df98..49cd23ff5d3c5541277e4da9df9266c755b51f32 100644
--- a/compiler/ppc/c-call.lisp
+++ b/compiler/ppc/c-call.lisp
@@ -7,7 +7,7 @@
 ;;; Scott Fahlman or slisp-group@cs.cmu.edu.
 ;;;
 (ext:file-comment
-  "$Header: /Volumes/share2/src/cmucl/cvs2git/cvsroot/src/compiler/ppc/c-call.lisp,v 1.2 2001/02/17 20:02:05 dtc Exp $")
+  "$Header: /Volumes/share2/src/cmucl/cvs2git/cvsroot/src/compiler/ppc/c-call.lisp,v 1.3 2003/07/20 13:53:11 emarsden Exp $")
 ;;;
 ;;; **********************************************************************
 ;;;
@@ -180,3 +180,16 @@
 	       (inst addi nsp-tn nsp-tn delta))
 	      (t
 	       (inst lwz nsp-tn nsp-tn 0)))))))
+
+
+;; bogus stubs for now
+
+(export '(make-callback-trampoline callback-accessor-form))
+
+(defun callback-accessor-form (type sp offset)
+  (error "Callbacks not implemented on Alpha"))
+
+(defun make-callback-trampoline (index return-type)
+  "Cons up a piece of code which calls call-callback with INDEX and a
+pointer to the arguments."
+  (error "Callbacks not implemented on Alpha"))