diff --git a/cmake/CMakeLists.txt b/cmake/CMakeLists.txt
index 28d8d569..d4b26294 100644
--- a/cmake/CMakeLists.txt
+++ b/cmake/CMakeLists.txt
@@ -110,6 +110,8 @@ if(WIN32)
   set (CMAKE_DEBUG_POSTFIX "d")
 endif(WIN32)
 
+SET(CMAKE_C_FLAGS_DEBUG "${CMAKE_C_FLAGS_DEBUG}  -D_DEBUG")
+
 #########################################################################
 # Windows CE
 #