Remove the lua_State* parameter from lua_callback

Wasn't used anyway.

src/catalua.cpp

@@ -724,7 +724,7 @@ int call_lua(std::string tocall)
 }
 
 
-void lua_callback(lua_State *, const char *callback_name)
+void lua_callback(const char *callback_name)
 {
     call_lua(std::string("mod_callback(\"") + std::string(callback_name) + "\")");
 }

src/catalua.h

@@ -32,7 +32,7 @@ int lua_mapgen(map *m, std::string terrain_type, mapgendata md, int t, float d,
 /**
  * Execute a callback that can be overriden by all mods.
  */
-void lua_callback(lua_State *L, const char *callback_name);
+void lua_callback(const char *callback_name);
 
 /**
  * Load the main file of a lua mod.

src/game.cpp

@@ -1203,7 +1203,7 @@ bool game::do_turn()
         calendar::turn.seconds() == 0) { // Midnight!
         overmap_buffer.process_mongroups();
 #ifdef LUA
-        lua_callback(lua_state, "on_day_passed");
+        lua_callback("on_day_passed");
 #endif
     }