debugTrace(DEBUG_gc, "push todo block %p (%ld words), step %d, todo_q: %ld",
bd->start, (unsigned long)(bd->free - bd->u.scan),
debugTrace(DEBUG_gc, "push todo block %p (%ld words), step %d, todo_q: %ld",
bd->start, (unsigned long)(bd->free - bd->u.scan),