diff --git a/src/corelib/Qt6CoreConfigExtras.cmake.in b/src/corelib/Qt6CoreConfigExtras.cmake.in
index 16f2ea00683..4a9f72a049b 100644
--- a/src/corelib/Qt6CoreConfigExtras.cmake.in
+++ b/src/corelib/Qt6CoreConfigExtras.cmake.in
@@ -26,7 +26,8 @@ if (NOT QT_NO_CREATE_TARGETS)
     set_property(TARGET ${__qt_core_target} PROPERTY INTERFACE_COMPILE_FEATURES cxx_decltype)
 endif()
 
-set(CMAKE_AUTOMOC_MACRO_NAMES "Q_OBJECT" "Q_GADGET" "Q_GADGET_EXPORT" "Q_NAMESPACE" "Q_NAMESPACE_EXPORT")
+list(APPEND CMAKE_AUTOMOC_MACRO_NAMES Q_OBJECT Q_GADGET Q_GADGET_EXPORT Q_NAMESPACE Q_NAMESPACE_EXPORT)
+list(REMOVE_DUPLICATES CMAKE_AUTOMOC_MACRO_NAMES)
 
 include("${CMAKE_CURRENT_LIST_DIR}/QtInstallPaths.cmake")