the garbage collection code uses the /sign/ of a pointer as a sort of flag.
pure evil. at least in my system, statically allocated and heap allocated
pointers have different signs. this patch replaces that with a more explicit
flag.

diff -Naur scheme-3.2-orig/architecture.c scheme-3.2/architecture.c
--- scheme-3.2-orig/architecture.c	1996-01-21 20:15:47.000000000 -0200
+++ scheme-3.2/architecture.c	2006-02-14 14:54:23.000000000 -0200
@@ -145,6 +145,7 @@
 	{
 		/* Enough space now, or was before. */
 		new = (Object)&Heap[Working][Free];
+		memset(new, 0, size);
 #if (ALIGNMENT-1)
 		/* Alignment (if not 1; defined in portable.h) */
 
diff -Naur scheme-3.2-orig/architecture.h scheme-3.2/architecture.h
--- scheme-3.2-orig/architecture.h	1996-01-21 20:15:48.000000000 -0200
+++ scheme-3.2/architecture.h	2006-02-14 14:57:40.000000000 -0200
@@ -95,16 +95,11 @@
 Import Object Move_Object();
 Import void Relocate();
 
-#if NEGATIVE_ADDRESSES
-	/* NEGATIVE_ADDRESSES defined in portable.h */
-#define Is_Forwarded(o) (((Integral_Pointer) Get_Type(o)) > 0)
-#else
-#define Is_Forwarded(o) (((Integral_Pointer) Get_Type(o)) < 0)
-#endif
+#define Is_Forwarded(o) Get_Forward_Flag(o)
+#define Get_Forwarding_Address(o) (Object)Get_Type(o)
+#define Set_Forwarding_Address(old, new) Get_Forward_Flag(old) = 1; \
+  Get_Type(old) = (Scheme_Type)new; 
 
-#define Get_Forwarding_Address(o) ((Object) (-((Integral_Pointer) Get_Type(o))))
-#define Set_Forwarding_Address(old,new) \
-		Get_Type(old) = (Scheme_Type) (-((Integral_Pointer)(new)))
 
 /* General */
 Import Object Copy_Object();
diff -Naur scheme-3.2-orig/object.h scheme-3.2/object.h
--- scheme-3.2-orig/object.h	1996-01-21 20:15:51.000000000 -0200
+++ scheme-3.2/object.h	2006-02-14 14:56:47.000000000 -0200
@@ -89,11 +89,13 @@
 {
 	Scheme_Type Type;
 	String Type_Name;
+	int forward_flag;
 } Common_Struct;
 
 /* And a way to access the common fields. */
 
 #define Get_Type(o) ((o)->Common.Type)
+#define Get_Forward_Flag(o) ((o)->Common.forward_flag)
 #define Get_Type_Name(o) ((o)->Common.Type_Name)
 
 #define Eval_Object(o)		((Get_Type(o)->Eval)(o))