[CMake] Add global definition of the lua macro

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})