allow a per-game seed in eressea.ini

src/kernel/save.c

@@ -1418,7 +1418,7 @@ int read_game(gamedata *data)
     read_attribs(data, &global.attribs, NULL);
     READ_INT(store, &turn);
     log_debug(" - reading turn %d", turn);
-    rng_init(turn);
+    rng_init(turn + config_get_int("game.seed", 0));
     READ_INT(store, NULL);          /* max_unique_id = ignore */
     READ_INT(store, &nextborder);
 

src/main.c

@@ -86,6 +86,7 @@ static const char * valid_keys[] = {
     "game.maxnmr",
     "game.name",
     "game.start",
+    "game.seed",
     "game.locale",
     "game.verbose",
     "game.report",