diff --git a/CMakeLists.txt b/CMakeLists.txt
index b0e87423cd9cf3f538c4e2f4b85dada65b1e28a7..a7982f0d7f255ef6393aed2f61dde047ba482d5a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -190,6 +190,7 @@ IF(LUA5_1_FOUND)
   LIST(APPEND HEADERS 
     ${${PROJECT_NAME}_MULTIBODY_PARSER_LUA_HEADERS}
     )
+  ADD_DEFINITIONS(-DWITH_LUA)
 ENDIF(LUA5_1_FOUND)
 
 PKG_CONFIG_APPEND_LIBS (${PROJECT_NAME})