Unknown arguments: (GENERATE_PRIVATE_CPP_EXPORTS)

CMake Error at /home/qt/work/install/lib/cmake/Qt6/QtCMakeHelpers.cmake:68 (message):
Unknown arguments: (GENERATE_PRIVATE_CPP_EXPORTS)
Call Stack (most recent call first):
 /home/qt/work/install/lib/cmake/Qt6/QtModuleHelpers.cmake:143 (_qt_internal_validate_all_args_are_parsed)
src/vncserver/CMakeLists.txt:5 (qt_internal_add_module)
-- Configuring incomplete, errors occurred!
See also "/home/qt/work/qt/tqtc-qtvncserver_build/CMakeFiles/CMakeOutput.log".
See also "/home/qt/work/qt/tqtc-qtvncserver_build/CMakeFiles/CMakeError.log".
CMake Error at /home/qt/work/install/lib/cmake/Qt6/QtProcessConfigureArgs.cmake:1062 (message):
CMake exited with code 1.