diff --git a/Source/cmake/OptionsQt.cmake b/Source/cmake/OptionsQt.cmake
--- a/Source/cmake/OptionsQt.cmake
+++ b/Source/cmake/OptionsQt.cmake
@@ -683,7 +683,6 @@ if (WIN32 AND COMPILER_IS_GCC_OR_CLANG)
 endif ()
 
 if (APPLE)
-    SET_AND_EXPOSE_TO_BUILD(HAVE_QOS_CLASSES 1)
 endif ()
 
 if (ENABLE_MATHML)