New options bit1 of isoburn_igopt_set_system_area() for isohybrid production

libisoburn/isoburn.c

@@ -1094,7 +1094,7 @@ int isoburn_igopt_set_system_area(struct isoburn_imgen_opts *opts,
    }
    memcpy(opts->system_area_data, data, 32768);
  }
- opts->system_area_options = options & 1;
+ opts->system_area_options = options & 3;
  return(1);
 }