WC2: make era usable for PvP

still disabled though

data/campaigns/World_Conquest/lua/era/era.lua

@@ -357,8 +357,11 @@ wc2_utils.menu_item {
 		if not wc2_era.get_faction(wesnoth.interface.get_viewing_side()) then
 			return false
 		end
-		if wc2_artifacts.is_item_at(x, y) then
-			return false
+		-- check whether wc2_artifacts is loaded
+		if wml.variables.wc2_scenario then
+			if wc2_artifacts.is_item_at(x, y) then
+				return false
+			end
 		end
 		return true
 	end,

data/campaigns/World_Conquest/lua/era_main.lua

@@ -1,4 +1,5 @@
 -- the main file for the WC2 mp era
 
 wc2_utils = wesnoth.require('./game_mechanics/utils.lua')
+wc2_color = wesnoth.require('./game_mechanics/color.lua')
 wc2_era = wesnoth.require('./era/era.lua')