diff --git a/ConfigureChecks.cmake b/ConfigureChecks.cmake
index fdbd5545..23ab2cad 100644
--- a/ConfigureChecks.cmake
+++ b/ConfigureChecks.cmake
@@ -221,7 +221,6 @@ if( WITH_KONQSIDEBAR )
   tde_save( CMAKE_REQUIRED_DEFINITIONS CMAKE_REQUIRED_FLAGS CMAKE_REQUIRED_INCLUDES CMAKE_REQUIRED_LIBRARIES )
   set( CMAKE_REQUIRED_DEFINITIONS ${TQT_CFLAGS_OTHER} )
   set( CMAKE_REQUIRED_INCLUDES ${TDE_INCLUDE_DIR};${TQT_INCLUDE_DIRS};${CMAKE_INCLUDE_PATH} )
-  set( CMAKE_REQUIRED_FLAGS "-include tqt.h" )
   foreach( _dirs ${TQT_LIBRARY_DIRS} )
     list( APPEND CMAKE_REQUIRED_LIBRARIES "-L${_dirs}" )
   endforeach()