diff --git a/src/javascript/CMakeLists.txt b/src/javascript/CMakeLists.txt
index e421b96..22569a6 100644
--- a/src/javascript/CMakeLists.txt
+++ b/src/javascript/CMakeLists.txt
@@ -12,6 +12,7 @@ include_directories (
   ${CMAKE_CURRENT_SOURCE_DIR}/..
 )
 
+set (CMAKE_CXX_FLAGS -DBUILDING_NODE_EXTENSION)
 set_source_files_properties (maajs.i PROPERTIES SWIG_FLAGS "-node")
 set_source_files_properties (maajs.i PROPERTIES CPLUSPLUS ON)