diff --git a/vm/mach_signal.c b/vm/mach_signal.c
index d373037b82..118fc7044c 100644
--- a/vm/mach_signal.c
+++ b/vm/mach_signal.c
@@ -7,7 +7,7 @@ Used under BSD license with permission from Paolo Bonzini and Bruno Haible,
 
 http://sourceforge.net/mailarchive/message.php?msg_name=200503102200.32002.bruno%40clisp.org
 
-Extensively modified for Factor - portions copyright (C) 2004-2007 Slava Pestov */
+Modified for Factor by Slava Pestov */
 
 #include "master.h"
 
diff --git a/vm/mach_signal.h b/vm/mach_signal.h
index ca46a4c32c..863fd86dae 100644
--- a/vm/mach_signal.h
+++ b/vm/mach_signal.h
@@ -1,3 +1,13 @@
+/* Fault handler information.  MacOSX version.
+Copyright (C) 1993-1999, 2002-2003  Bruno Haible <clisp.org at bruno>
+Copyright (C) 2003  Paolo Bonzini <gnu.org at bonzini>
+
+Used under BSD license with permission from Paolo Bonzini and Bruno Haible,
+2005-03-10:
+
+http://sourceforge.net/mailarchive/message.php?msg_name=200503102200.32002.bruno%40clisp.org
+
+Modified for Factor by Slava Pestov */
 #include <stdio.h>
 #include <stdlib.h>
 #include <errno.h>
diff --git a/vm/os-macosx-ppc.h b/vm/os-macosx-ppc.h
index f3a5de88c2..b6c2cc6859 100644
--- a/vm/os-macosx-ppc.h
+++ b/vm/os-macosx-ppc.h
@@ -1,3 +1,13 @@
+/* Fault handler information.  MacOSX version.
+Copyright (C) 1993-1999, 2002-2003  Bruno Haible <clisp.org at bruno>
+Copyright (C) 2003  Paolo Bonzini <gnu.org at bonzini>
+
+Used under BSD license with permission from Paolo Bonzini and Bruno Haible,
+2005-03-10:
+
+http://sourceforge.net/mailarchive/message.php?msg_name=200503102200.32002.bruno%40clisp.org
+
+Modified for Factor by Slava Pestov */
 #define FRAME_RETURN_ADDRESS(frame) *((XT *)(frame_successor(frame) + 1) + 2)
 
 #define MACH_EXC_STATE_TYPE ppc_exception_state_t
@@ -8,15 +18,15 @@
 #define MACH_THREAD_STATE_COUNT PPC_THREAD_STATE_COUNT
 
 #if __DARWIN_UNIX03
-    #define MACH_EXC_STATE_FAULT(exc_state) (exc_state)->__dar
-    #define MACH_STACK_POINTER(thr_state) (thr_state)->__r1
-    #define MACH_PROGRAM_COUNTER(thr_state) (thr_state)->__srr0
-    #define UAP_PROGRAM_COUNTER(ucontext) \
+	#define MACH_EXC_STATE_FAULT(exc_state) (exc_state)->__dar
+	#define MACH_STACK_POINTER(thr_state) (thr_state)->__r1
+	#define MACH_PROGRAM_COUNTER(thr_state) (thr_state)->__srr0
+	#define UAP_PROGRAM_COUNTER(ucontext) \
 		MACH_PROGRAM_COUNTER(&(((ucontext_t *)(ucontext))->uc_mcontext->__ss))
 #else
-    #define MACH_EXC_STATE_FAULT(exc_state) (exc_state)->dar
-    #define MACH_STACK_POINTER(thr_state) (thr_state)->r1
-    #define MACH_PROGRAM_COUNTER(thr_state) (thr_state)->srr0
-    #define UAP_PROGRAM_COUNTER(ucontext) \
+	#define MACH_EXC_STATE_FAULT(exc_state) (exc_state)->dar
+	#define MACH_STACK_POINTER(thr_state) (thr_state)->r1
+	#define MACH_PROGRAM_COUNTER(thr_state) (thr_state)->srr0
+	#define UAP_PROGRAM_COUNTER(ucontext) \
 		MACH_PROGRAM_COUNTER(&(((ucontext_t *)(ucontext))->uc_mcontext->ss))
 #endif
diff --git a/vm/os-macosx-x86.32.h b/vm/os-macosx-x86.32.h
index d335c4abd4..b77a0c7742 100644
--- a/vm/os-macosx-x86.32.h
+++ b/vm/os-macosx-x86.32.h
@@ -1,3 +1,13 @@
+/* Fault handler information.  MacOSX version.
+Copyright (C) 1993-1999, 2002-2003  Bruno Haible <clisp.org at bruno>
+Copyright (C) 2003  Paolo Bonzini <gnu.org at bonzini>
+
+Used under BSD license with permission from Paolo Bonzini and Bruno Haible,
+2005-03-10:
+
+http://sourceforge.net/mailarchive/message.php?msg_name=200503102200.32002.bruno%40clisp.org
+
+Modified for Factor by Slava Pestov */
 #define MACH_EXC_STATE_TYPE i386_exception_state_t
 #define MACH_EXC_STATE_FLAVOR i386_EXCEPTION_STATE
 #define MACH_EXC_STATE_COUNT i386_EXCEPTION_STATE_COUNT
@@ -6,15 +16,15 @@
 #define MACH_THREAD_STATE_COUNT i386_THREAD_STATE_COUNT
 
 #if __DARWIN_UNIX03
-    #define MACH_EXC_STATE_FAULT(exc_state) (exc_state)->__faultvaddr
-    #define MACH_STACK_POINTER(thr_state) (thr_state)->__esp
-    #define MACH_PROGRAM_COUNTER(thr_state) (thr_state)->__eip
+	#define MACH_EXC_STATE_FAULT(exc_state) (exc_state)->__faultvaddr
+	#define MACH_STACK_POINTER(thr_state) (thr_state)->__esp
+	#define MACH_PROGRAM_COUNTER(thr_state) (thr_state)->__eip
 	#define UAP_PROGRAM_COUNTER(ucontext) \
 		MACH_PROGRAM_COUNTER(&(((ucontext_t *)(ucontext))->uc_mcontext->__ss))
 #else
-    #define MACH_EXC_STATE_FAULT(exc_state) (exc_state)->faultvaddr
-    #define MACH_STACK_POINTER(thr_state) (thr_state)->esp
-    #define MACH_PROGRAM_COUNTER(thr_state) (thr_state)->eip
+	#define MACH_EXC_STATE_FAULT(exc_state) (exc_state)->faultvaddr
+	#define MACH_STACK_POINTER(thr_state) (thr_state)->esp
+	#define MACH_PROGRAM_COUNTER(thr_state) (thr_state)->eip
 	#define UAP_PROGRAM_COUNTER(ucontext) \
 		MACH_PROGRAM_COUNTER(&(((ucontext_t *)(ucontext))->uc_mcontext->ss))	
 #endif