when compile oxce i get link error 2001. 1>Map.obj : error LNK2001: неразрешенный внешний символ ""public: void __thiscall OpenXcom::ItemSprite::drawShadow(class OpenXcom::BattleItem *,int,int,bool)" (?drawShadow@ItemSprite@OpenXcom@@QAEXPAVBattleItem@2@HH_N@Z)". What is?