diff --git a/include/vkd3d_windows.h b/include/vkd3d_windows.h
index c2786cf1..a030d1be 100644
--- a/include/vkd3d_windows.h
+++ b/include/vkd3d_windows.h
@@ -23,7 +23,6 @@
 #ifndef __VKD3D_WINDOWS_H
 #define __VKD3D_WINDOWS_H
 
-
 #if !defined(_WIN32) || defined(__WIDL__)
 
 /* HRESULT */
@@ -143,9 +142,6 @@ typedef struct SECURITY_ATTRIBUTES SECURITY_ATTRIBUTES;
 #  define DECLSPEC_HIDDEN __attribute__((visibility("hidden")))
 # endif
 
-# define __C89_NAMELESS
-# define __C89_NAMELESSUNIONNAME
-
 /* Macros for COM interfaces */
 # define interface struct
 # define BEGIN_INTERFACE
@@ -180,11 +176,17 @@ typedef struct SECURITY_ATTRIBUTES SECURITY_ATTRIBUTES;
 
 # include <windows.h>
 
-# ifndef __C89_NAMELESS
-#  define __C89_NAMELESS
-#  define __C89_NAMELESSUNIONNAME
-# endif  /* __C89_NAMELESS */
-
 #endif  /* _WIN32 */
 
+
+#ifndef __C89_NAMELESS
+# ifdef NONAMELESSUNION
+#  define __C89_NAMELESS
+#  define __C89_NAMELESSUNIONNAME u
+# else
+#  define __C89_NAMELESS
+#  define __C89_NAMELESSUNIONNAME
+# endif /* NONAMELESSUNION */
+#endif  /* __C89_NAMELESS */
+
 #endif  /* __VKD3D_WINDOWS_H */
diff --git a/libs/vkd3d/vkd3d_private.h b/libs/vkd3d/vkd3d_private.h
index cf22303e..f9116b70 100644
--- a/libs/vkd3d/vkd3d_private.h
+++ b/libs/vkd3d/vkd3d_private.h
@@ -24,6 +24,7 @@
 #define __VKD3D_PRIVATE_H
 
 #define COBJMACROS
+#define NONAMELESSUNION
 #include "vkd3d_common.h"
 #include "vkd3d_debug.h"
 #include "vkd3d_vulkan.h"