add rough support for getting gameid pre 5.7

src/gameid.lua

@@ -2,7 +2,27 @@ local game_alias = {
     mineclone2 = "mineclonia",
 }
 
-local gameid = minetest.get_game_info().id
+local game_modnames = {
+    mineclonia = "mcl_core",
+    farlands_reloaded = "fl_core",
+    minetest = "default",
+    hades = "hades_core",
+    exile = "exile_env_sounds",
+    ksurvive2 = "ks_metals",
+}
+
+local gameid = "xcompat_unknown_gameid"
+
+if type(minetest.get_game_info) == "function" then
+    gameid = minetest.get_game_info().id
+else
+    for game, modname in pairs(game_modnames) do
+        if minetest.get_modpath(modname) then
+            gameid = game
+            break
+        end
+    end
+end
 
 --for games that are similar/derviatives of other games
 if game_alias[gameid] then gameid = game_alias[gameid] end