diff --git a/src/gl/system/gl_system.h b/src/gl/system/gl_system.h
index e5abe2ec5..db7f1f890 100644
--- a/src/gl/system/gl_system.h
+++ b/src/gl/system/gl_system.h
@@ -1,40 +1,6 @@
 #ifndef __GL_PCH_H
 #define __GL_PCH_H
-#ifdef _WIN32
-//#define __RPCNDR_H__		// this header causes problems!
-//#define __wtypes_h__
-#define WIN32_LEAN_AND_MEAN
-#define _WIN32_WINDOWS 0x410
-#ifndef _WIN32_WINNT
-#define _WIN32_WINNT 0x0501			// Support the mouse wheel and session notification.
-#define _WIN32_IE 0x0500
-#endif
-#define DIRECTINPUT_VERSION 0x800
-#define DIRECTDRAW_VERSION 0x0300
 
-#define DWORD WINDOWS_DWORD	// I don't want to depend on this throughout the GL code!
-
-#ifdef _MSC_VER
-#pragma warning(disable : 4995)     // MIPS
-#endif
-
-#include <windows.h>
-#include <mmsystem.h>
-#include <winsock.h>
-#ifndef __WINE__
-#include <dshow.h>
-#endif
-#include <d3d9.h>
-//#include <dsound.h>
-//#include <dinput.h>
-//#include <lmcons.h>
-//#include <shlobj.h>
-#endif
-
-#undef DWORD
-#ifndef CALLBACK
-#define CALLBACK
-#endif
 #include <math.h>
 #include <float.h>
 #include <limits.h>
@@ -73,33 +39,6 @@
 	#include <OpenGL/OpenGL.h>
 #endif
 
-#ifdef _WIN32
-#define DWORD WINDOWS_DWORD	// I don't want to depend on this throughout the GL code!
-//#include "gl/api/wglext.h"
-#ifndef __WINE__
-#undef DWORD
-#endif
-#else
-typedef unsigned char 	byte;
-typedef float		FLOAT;
-template <typename T>
-inline T max( T a, T b) { return (((a)>(b)) ? (a) : (b)); }
-#define _access(a,b)	access(a,b)
-#endif
-
-
-#ifdef LoadMenu
-#undef LoadMenu
-#endif
-#ifdef DrawText
-#undef DrawText
-#endif
-#ifdef GetCharWidth
-#undef GetCharWidth
-#endif
-
-#undef S_NORMAL
-#undef OPAQUE
 
 
 #ifdef _MSC_VER
@@ -111,7 +50,4 @@ inline T max( T a, T b) { return (((a)>(b)) ? (a) : (b)); }
 #pragma warning(disable : 4305)     // truncate from double to float
 #endif
 
-#ifdef WIN32
-#undef WIN32
-#endif
 #endif //__GL_PCH_H
diff --git a/src/win32/win32gliface.h b/src/win32/win32gliface.h
index 463220a99..cd7e508d3 100644
--- a/src/win32/win32gliface.h
+++ b/src/win32/win32gliface.h
@@ -9,7 +9,6 @@
 extern IVideo *Video;
 
 
-extern BOOL AppActive;
 
 EXTERN_CVAR (Float, dimamount)
 EXTERN_CVAR (Color, dimcolor)
@@ -19,8 +18,6 @@ EXTERN_CVAR(Int, vid_defheight);
 EXTERN_CVAR(Int, vid_renderer);
 EXTERN_CVAR(Int, vid_adapter);
 
-extern HINSTANCE g_hInst;
-extern HWND Window;
 extern IVideo *Video;
 
 struct FRenderer;
@@ -43,7 +40,7 @@ public:
 	// unused but must be defined
 	virtual void Blank ();
 	virtual bool PaintToWindow ();
-	virtual HRESULT GetHR();
+	virtual long/*HRESULT*/ GetHR();	// windows.h pollution prevention.
 
 	virtual bool CreateResources ();
 	virtual void ReleaseResources ();
@@ -76,12 +73,12 @@ protected:
 	void SetGammaTable(uint16_t * tbl);
 
 	float m_Gamma, m_Brightness, m_Contrast;
-	WORD m_origGamma[768];
-	BOOL m_supportsGamma;
+	uint16_t m_origGamma[768];
+	bool m_supportsGamma;
 	bool m_Fullscreen;
 	int m_Width, m_Height, m_Bits, m_RefreshHz;
 	int m_Lock;
-	char m_displayDeviceNameBuffer[CCHDEVICENAME];
+	char m_displayDeviceNameBuffer[32/*CCHDEVICENAME*/];	// do not use windows.h constants here!
 	char *m_displayDeviceName;
 	int SwapInterval;
 
diff --git a/src/win32/win32iface.h b/src/win32/win32iface.h
index 8db27304d..03ae6ffde 100644
--- a/src/win32/win32iface.h
+++ b/src/win32/win32iface.h
@@ -34,21 +34,8 @@
 #ifndef __WIN32IFACE_H
 #define __WIN32IFACE_H
 
-#ifndef DIRECTDRAW_VERSION
-#define DIRECTDRAW_VERSION 0x0300
-#endif
-#ifndef DIRECT3D_VERSION
-#define DIRECT3D_VERSION 0x0900
-#endif
-
-#define WIN32_LEAN_AND_MEAN
-#include <windows.h>
-#include <ddraw.h>
-#include <d3d9.h>
-
 #include "hardware.h"
 
-#define SAFE_RELEASE(x)		{ if (x != NULL) { x->Release(); x = NULL; } }
 
 EXTERN_CVAR (Bool, vid_vsync)