diff --git a/reactos/include/psdk/windef.h b/reactos/include/psdk/windef.h
index d4bcabe27ab..40e11191aed 100644
--- a/reactos/include/psdk/windef.h
+++ b/reactos/include/psdk/windef.h
@@ -171,6 +171,7 @@ extern "C" {
 #define _ANONYMOUS_UNION
 #define _UNION_NAME(x) x
 #define DUMMYUNIONNAME	u
+#define DUMMYUNIONNAME1	u1
 #define DUMMYUNIONNAME2	u2
 #define DUMMYUNIONNAME3	u3
 #define DUMMYUNIONNAME4	u4
@@ -181,6 +182,7 @@ extern "C" {
 #else
 #define _UNION_NAME(x)
 #define DUMMYUNIONNAME
+#define DUMMYUNIONNAME1
 #define DUMMYUNIONNAME2
 #define DUMMYUNIONNAME3
 #define DUMMYUNIONNAME4
@@ -193,13 +195,19 @@ extern "C" {
 #define _ANONYMOUS_STRUCT
 #define _STRUCT_NAME(x) x
 #define DUMMYSTRUCTNAME	s
+#define DUMMYSTRUCTNAME1 s1
 #define DUMMYSTRUCTNAME2 s2
 #define DUMMYSTRUCTNAME3 s3
+#define DUMMYSTRUCTNAME4 s4
+#define DUMMYSTRUCTNAME5 s5
 #else
 #define _STRUCT_NAME(x)
 #define DUMMYSTRUCTNAME
+#define DUMMYSTRUCTNAME1
 #define DUMMYSTRUCTNAME2
 #define DUMMYSTRUCTNAME3
+#define DUMMYSTRUCTNAME4
+#define DUMMYSTRUCTNAME5
 #endif
 
 #ifndef NO_STRICT