diff --git a/include/ddk/wdm.h b/include/ddk/wdm.h
index 4f1523395da..b15bea4b1cd 100644
--- a/include/ddk/wdm.h
+++ b/include/ddk/wdm.h
@@ -1,6 +1,15 @@
 #ifndef _WDMDDK_
 #define _WDMDDK_
 
+/* Helper macro to enable gcc's extension.  */
+#ifndef __GNU_EXTENSION
+#ifdef __GNUC__
+#define __GNU_EXTENSION __extension__
+#else
+#define __GNU_EXTENSION
+#endif
+#endif
+
 //
 // Dependencies
 //