-#else
-#define SCM_JBDFRAME(x) ((scm_debug_frame *) SCM_CELL_WORD_0 (SCM_CDR (x)))
-#define JBJMPBUF(OBJ) ((jmp_buf *) SCM_CELL_WORD_1 (SCM_CDR (OBJ)))
-#define SCM_SETJBDFRAME(OBJ,X) (SCM_SET_CELL_WORD_0 (SCM_CDR (OBJ), (X)))
-#define SETJBJMPBUF(OBJ,X) (SCM_SET_CELL_WORD_1 (SCM_CDR (OBJ), (X)))
-
-static scm_sizet
-freejb (SCM jbsmob)
-{
- scm_must_free ((char *) SCM_CELL_WORD_1 (jbsmob));
- return sizeof (scm_cell);
-}
+#ifdef DEBUG_EXTENSIONS
+#define SCM_JBDFRAME(x) ((scm_debug_frame *) SCM_CELL_WORD_2 (x))
+#define SCM_SETJBDFRAME(x,v) (SCM_SET_CELL_WORD_2 ((x), (v)))