default: lava cooling: look as well for basalt from illuna_extras

mods/default/functions.lua

@@ -126,8 +126,12 @@ lavagen = {
 }
 
 -- thanks to ElectronLibre from Minetest IRC
-if minetest.get_modpath("darkage")
-    then table.insert(lavagen, "darkage:basalt")
+if minetest.get_modpath("darkage") then
+    table.insert(lavagen, "darkage:basalt")
+else
+    if minetest.get_modpath("illuna_extras") then
+        table.insert(lavagen, "darkage:basalt")
+    end
 end
 
 default.cool_lava = function(pos, node)