$blitz.obj : error LNK2019: unresolved external symbol "void __cdecl Upp::WakeUpGuiThread(void)" (?WakeUpGuiThread@Upp@@YAXXZ) referenced in function "public: static void __cdecl Upp::Ctrl::Call(class Upp::Callback)" (?Call@Ctrl@Upp@@SAXVCallback@2@@Z)