[FIX] - problems if cuda was found but not enabled.

src/modules/detTractClustering/CMakeLists.txt

@@ -43,7 +43,7 @@ SET( MODULE_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR} )
 COLLECT_COMPILE_FILES( "${MODULE_SOURCE_DIR}" TARGET_CPP_FILES TARGET_H_FILES TARGET_TEST_FILES )
 
 # for cuda, we need to do some special stuff first
-IF( CUDA_FOUND )
+IF( CUDA_FOUND AND OW_USE_CUDA )
     FILE( GLOB_RECURSE CUDA_SRC "*.cu" )
     CUDA_ADD_LIBRARY( ${MODULE_NAME} SHARED ${TARGET_CPP_FILES} ${TARGET_H_FILES} ${CUDA_SRC} )
     TARGET_LINK_LIBRARIES( ${MODULE_NAME} ${OWCoreName} ${CUDA_LIBRARIES} )