if (!(mm_flags & MM_IWMMXT)) return;
void MPV_common_init_iwmmxt(MpegEncContext *s){    s->dct_unquantize_h263_intra = dct_unquantize_h263_intra_iwmmxt;#if 0    s->dct_unquantize_h263_inter = dct_unquantize_h263_inter_iwmmxt;#endif}