diff --git a/winsup/w32api/include/objbase.h b/winsup/w32api/include/objbase.h
index 71d10977d..e4f8ad607 100644
--- a/winsup/w32api/include/objbase.h
+++ b/winsup/w32api/include/objbase.h
@@ -5,6 +5,7 @@
 
 #ifndef _OBJBASE_H
 #define _OBJBASE_H
+#define _OBJBASE_H_
 #if __GNUC__ >=3
 #pragma GCC system_header
 #endif
diff --git a/winsup/w32api/include/wingdi.h b/winsup/w32api/include/wingdi.h
index 7be8a5b29..fbde26802 100644
--- a/winsup/w32api/include/wingdi.h
+++ b/winsup/w32api/include/wingdi.h
@@ -1,5 +1,6 @@
 #ifndef _WINGDI_H
 #define _WINGDI_H
+#define _WINGDI_
 #if __GNUC__ >= 3
 #pragma GCC system_header
 #endif