(WORLD_SZ): New.

(isok, ef_init, bmaps_intersect, bp_init, player_accept)
(finish_sects, main): Use it.

(bp_neighbors, bp_lbcost, pathcost): Use XYOFFSET().  No
functional change.

src/util/files.c

@@ -196,7 +196,7 @@ main(int argc, char *argv[])
 	    putsect(&sct);
 	}
     }
-    map = calloc(WORLD_X * WORLD_Y / 2, sizeof(*map));
+    map = calloc(WORLD_SZ(), sizeof(*map));
     for (i = 0; i < MAXNOC; i++) {
 	ef_write(EF_MAP, i, map);
     }