3m: fix zeroing out of weak-box secondary pointer when the secondary pointer has moved in the mark phase

svn: r6704

src/mzscheme/gc2/compact.c

@@ -532,6 +532,7 @@ static int size_on_free_list(void *p)
 /******************************************************************************/
 
 static int is_marked(void *p);
+#define weak_box_resolve(p) (p)
 
 #include "weak.c"
 

src/mzscheme/gc2/newgc.c

@@ -1170,6 +1170,8 @@ static unsigned short ephemeron_tag;
 #define is_marked(p) marked(p)
 typedef short Type_Tag;
 
+#define weak_box_resolve(p) GC_resolve(p)
+
 #include "weak.c"
 
 /*****************************************************************************/

src/mzscheme/gc2/weak.c

@@ -223,7 +223,9 @@ static void zero_weak_boxes()
     if (!is_marked(wb->val)) {
       wb->val = NULL;
       if (wb->secondary_erase) {
-	*(wb->secondary_erase + wb->soffset) = NULL;
+        void **p;
+        p = (void **)GC_resolve(wb->secondary_erase);
+	*(p + wb->soffset) = NULL;
 	wb->secondary_erase = NULL;
       }
     }