diff --git a/CMakeLists.txt b/CMakeLists.txt
index d794ecf..ea002e0 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -169,6 +169,8 @@ endif( GLIB2_FOUND )
 
 ##### check for Qt3 and TQt #####################
 
+include( CheckCXXSourceCompiles )
+
 find_package( Qt )
 find_package( TQt )