diff --git a/CMakeLists.txt b/CMakeLists.txt
index 583a6e0fa..8e1d1b5d4 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -379,6 +379,7 @@ ENDIF()
 SET(CMAKE_C_FLAGS "${WERROR_FLAGS} ${CMAKE_C_FLAGS}")
 SET(CMAKE_CXX_FLAGS "-fno-exceptions ${WERROR_FLAGS} ${CMAKE_CXX_FLAGS}")
 SET(CMAKE_C_FLAGS_DEBUG "${CMAKE_C_FLAGS_DEBUG} -DLMMS_DEBUG")
+SET(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -DLMMS_DEBUG")
 
 
 # people simply updating git will still have this and mess up build with it