StgWord32 blocks; /* no. of blocks (if grp head, 0 otherwise) */
StgWord32 flags; /* block is in to-space */
#if SIZEOF_VOID_P == 8
StgWord32 blocks; /* no. of blocks (if grp head, 0 otherwise) */
StgWord32 flags; /* block is in to-space */
#if SIZEOF_VOID_P == 8