diff --git a/dlls/uuid/uuid.c b/dlls/uuid/uuid.c
index 21b0ee1edcd..2b30313e7de 100644
--- a/dlls/uuid/uuid.c
+++ b/dlls/uuid/uuid.c
@@ -21,6 +21,7 @@
 
 #include <stdarg.h>
 
+#include "windef.h"
 #define COM_NO_WINDOWS_H
 #include "initguid.h"
 
diff --git a/include/guiddef.h b/include/guiddef.h
index 749a37cee54..8ad314e0f6b 100644
--- a/include/guiddef.h
+++ b/include/guiddef.h
@@ -32,16 +32,18 @@ typedef struct _GUID
 #ifdef INITGUID
 #ifdef __cplusplus
 #define DEFINE_GUID(name, l, w1, w2, b1, b2, b3, b4, b5, b6, b7, b8) \
+        EXTERN_C const GUID name DECLSPEC_HIDDEN; \
         EXTERN_C const GUID name = \
 	{ l, w1, w2, { b1, b2,  b3,  b4,  b5,  b6,  b7,  b8 } }
 #else
 #define DEFINE_GUID(name, l, w1, w2, b1, b2, b3, b4, b5, b6, b7, b8) \
+        const GUID name DECLSPEC_HIDDEN; \
         const GUID name = \
 	{ l, w1, w2, { b1, b2,  b3,  b4,  b5,  b6,  b7,  b8 } }
 #endif
 #else
 #define DEFINE_GUID(name, l, w1, w2, b1, b2, b3, b4, b5, b6, b7, b8) \
-    EXTERN_C const GUID name
+    EXTERN_C const GUID name DECLSPEC_HIDDEN
 #endif
 
 #define DEFINE_OLEGUID(name, l, w1, w2) \