;   int Al = cinfo->Al;   JBLOCKROW block;    entropy->next_output_byte = cinfo->dest->next_output_byte;   entropy->free_in_buffer = cinfo->dest->free_in_buffer;    /* Emit restart marker if needed */   if (cinfo->restart_interval)     if (entropy->restarts_to_go == 0)       emit_restart(entropy, entropy->next_restart_num);    /* Encode the MCU data blocks */   for (blkn = 0; blkn < cinfo->blocks_in_MCU; blkn++) {     block = MCU_data[blkn];     