diff --git a/reactos/include/ddk/ntddk.h b/reactos/include/ddk/ntddk.h
index b049f287676..5a02c6f6a8b 100644
--- a/reactos/include/ddk/ntddk.h
+++ b/reactos/include/ddk/ntddk.h
@@ -32,7 +32,6 @@
 #endif
 
 #include <stdarg.h>
-#include <windef.h>
 #include <excpt.h>
 #include <ntdef.h>
 #include <basetyps.h>
diff --git a/reactos/include/psdk/ntdef.h b/reactos/include/ddk/ntdef.h
similarity index 98%
rename from reactos/include/psdk/ntdef.h
rename to reactos/include/ddk/ntdef.h
index b7b202bdf6b..3c1d4e1abb8 100644
--- a/reactos/include/psdk/ntdef.h
+++ b/reactos/include/ddk/ntdef.h
@@ -1,8 +1,5 @@
 #ifndef _NTDEF_H
 #define _NTDEF_H
-#if __GNUC__ >=3
-#pragma GCC system_header
-#endif
 
 #include <stdarg.h>
 #include <windef.h>
@@ -114,11 +111,11 @@ typedef LIST_ENTRY64 *PLIST_ENTRY64;
 #define RTL_FIELD_SIZE(type, field) (sizeof(((type *)0)->field))
 #define RTL_NUMBER_OF_V1(A) (sizeof(A)/sizeof((A)[0]))
 #define RTL_NUMBER_OF_V2(A) RTL_NUMBER_OF_V1(A)
-#endif
 #ifdef ENABLE_RTL_NUMBER_OF_V2
 #define RTL_NUMBER_OF(A) RTL_NUMBER_OF_V2(A)
 #else
 #define RTL_NUMBER_OF(A) RTL_NUMBER_OF_V1(A)
+#endif
 #define ARRAYSIZE(A)    RTL_NUMBER_OF_V2(A)
 #define MINCHAR   0x80
 #define MAXCHAR   0x7f
diff --git a/reactos/include/ddk/portcls.h b/reactos/include/ddk/portcls.h
index 33e46ccb649..39cf3932b6f 100644
--- a/reactos/include/ddk/portcls.h
+++ b/reactos/include/ddk/portcls.h
@@ -123,7 +123,6 @@
 #ifndef PORTCLS_H
 #define PORTCLS_H
 
-//#include <windef.h>
 #include <ks.h>
 #include <punknown.h>
 #include <ntddk.h>
diff --git a/reactos/include/ddk/punknown.h b/reactos/include/ddk/punknown.h
index ef75fb87c75..b1f105debf7 100644
--- a/reactos/include/ddk/punknown.h
+++ b/reactos/include/ddk/punknown.h
@@ -8,7 +8,7 @@
 #ifndef _UNKNOWN_H_
 #define _UNKNOWN_H_
 
-#include <windef.h>
+#include <ntdef.h>
 #define COM_NO_WINDOWS_H
 #include <basetyps.h>
 
diff --git a/reactos/include/ddk/unknown.h b/reactos/include/ddk/unknown.h
index fd00a64224f..9aaee5be3a1 100644
--- a/reactos/include/ddk/unknown.h
+++ b/reactos/include/ddk/unknown.h
@@ -9,7 +9,7 @@ extern "C" {
 #include <wdm.h>
 #endif
 
-#include <windef.h>
+#include <ntdef.h>
 #define COM_NO_WINDOWS_H
 #include <basetyps.h>
 #ifdef PUT_GUIDS_HERE
diff --git a/reactos/include/reactos/debug.h b/reactos/include/reactos/debug.h
index 10d36fa0f20..8e31feb9ea8 100644
--- a/reactos/include/reactos/debug.h
+++ b/reactos/include/reactos/debug.h
@@ -20,7 +20,7 @@
 #if !defined(_RTLFUNCS_H) && (!defined(_NTDDK_) || !defined(__NTDDK_H))
 
 /* Make sure we have basic types (some people include us *before* SDK... */
-#if !defined(_NTDEF_) && !defined(_WINDEF_) && !defined(_WINDEF_H)
+#if !defined(_NTDEF_) && !defined(_NTDEF_H) && !defined(_WINDEF_) && !defined(_WINDEF_H)
 #error Please include SDK first.
 #endif