- make_oakengine_gtest embeds oakengine-obj; test code must see OAKENGINE_API as dllexport too (OAKENGINE_BUILD), otherwise MinGW resolves nothing against __imp_* stubs - the render worker intentionally drops QT_QPA_PLATFORM=offscreen and needs a real display for its GL context; run the Linux ctest and the filtered gtest steps under xvfb-run