*/
void delta_3waymerge_cmd(void){
  Blob pivot, v1, v2, merged;
  if( g.argc!=6 ){
    usage("PIVOT V1 V2 MERGED");
  }
  if( blob_read_from_file(&pivot, g.argv[2])<0 ){
    fprintf(stderr,"cannot read %s\n", g.argv[2]);
    fossil_exit(1);
  }
  if( blob_read_from_file(&v1, g.argv[3])<0 ){
    fprintf(stderr,"cannot read %s\n", g.argv[3]);
    fossil_exit(1);
  }
  if( blob_read_from_file(&v2, g.argv[4])<0 ){
    fprintf(stderr,"cannot read %s\n", g.argv[4]);
    fossil_exit(1);
  }
  blob_merge(&pivot, &v1, &v2, &merged);
  if( blob_write_to_file(&merged, g.argv[5])<blob_size(&merged) ){
    fprintf(stderr,"cannot write %s\n", g.argv[4]);
    fossil_exit(1);
  }
  blob_reset(&pivot);
  blob_reset(&v1);
  blob_reset(&v2);
  blob_reset(&merged);
}