diff --git a/tqt/CMakeLists.txt b/tqt/CMakeLists.txt
index e20261c..f366481 100644
--- a/tqt/CMakeLists.txt
+++ b/tqt/CMakeLists.txt
@@ -30,7 +30,7 @@ ADD_CUSTOM_COMMAND(OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/mangled.h
 		COMMAND ${CMAKE_SOURCE_DIR}/mangled.sh ${CMAKE_CXX_COMPILER} ${CMAKE_CURRENT_BINARY_DIR}/mangled.h)
 
 set(kqt3_SRCS kqt3.cpp mangled.h)
-add_definitions(${QT_DEFINITIONS} -DQT_CLEAN_NAMESPACE -DTQT_THREAD_SUPPORT)
+add_definitions(${QT_DEFINITIONS} -DTQT_THREAD_SUPPORT)
 add_library(kqt3 SHARED ${kqt3_SRCS})
 target_link_libraries(kqt3 ${TQT_LIBRARIES} -lc -ldl)
 install(TARGETS kqt3 LIBRARY DESTINATION ${LIB_INSTALL_DIR}/kgtk)