The build system does not work accept -DFEATURE_cxx20:BOOL=TRUE

cmake] CMake Error at qtbase/cmake/QtFeature.cmake:545 (message):
[cmake]   cxx20 has unexpected value "TRUE"! Valid values are ON, OFF and UNSET.
[cmake] Call Stack (most recent call first):
[cmake]   qtbase/cmake/QtFeature.cmake:553 (qt_internal_generate_feature_line)
[cmake]   qtbase/cmake/QtFeature.cmake:653 (qt_internal_feature_write_file)
[cmake]   qtbase/cmake/QtBaseGlobalTargets.cmake:103 (qt_feature_module_end)
[cmake]   qtbase/CMakeLists.txt:107 (include)