diff --git a/include/cpu.h b/include/cpu.h
index 75a746ca..ac6b6489 100644
--- a/include/cpu.h
+++ b/include/cpu.h
@@ -16,12 +16,18 @@
  *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  */
 
-#ifndef __CPU_H
-#define __CPU_H
+#ifndef DOSBOX_CPU_H
+#define DOSBOX_CPU_H
 
+#ifndef DOSBOX_DOSBOX_H
 #include "dosbox.h" 
+#endif
+#ifndef DOSBOX_REGS_H
 #include "regs.h"
+#endif
+#ifndef DOSBOX_MEM_H
 #include "mem.h"
+#endif
 
 /* CPU Cycle Timing */
 extern Bits CPU_Cycles;
@@ -418,4 +424,3 @@ INLINE void CPU_SetFlagsw(Bitu word) {
 
 
 #endif
-
diff --git a/include/cross.h b/include/cross.h
index f68bd5ad..e9b750ed 100644
--- a/include/cross.h
+++ b/include/cross.h
@@ -16,10 +16,10 @@
  *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  */
 
-/* $Id: cross.h,v 1.12 2005-02-10 10:20:47 qbix79 Exp $ */
+/* $Id: cross.h,v 1.13 2005-03-24 10:18:45 qbix79 Exp $ */
 
-#ifndef _CROSS_H
-#define _CROSS_H
+#ifndef DOSBOX_CROSS_H
+#define DOSBOX_CROSS_H
 
 #include <stdio.h>
 #include <sys/stat.h>
@@ -57,4 +57,3 @@
 #endif
 
 #endif
-
diff --git a/include/dma.h b/include/dma.h
index e4ffc803..fb72a2ea 100644
--- a/include/dma.h
+++ b/include/dma.h
@@ -16,10 +16,10 @@
  *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  */
 
-/* $Id: dma.h,v 1.13 2005-02-10 10:20:47 qbix79 Exp $ */
+/* $Id: dma.h,v 1.14 2005-03-24 10:18:45 qbix79 Exp $ */
 
-#ifndef __DMA_H
-#define __DMA_H
+#ifndef DOSBOX_DMA_H
+#define DOSBOX_DMA_H
 
 enum DMAEvent {
 	DMA_REACHED_TC,
@@ -89,5 +89,3 @@ extern DmaChannel *DmaChannels[8];
 extern DmaController *DmaControllers[2];
 
 #endif
-
-
diff --git a/include/dos_inc.h b/include/dos_inc.h
index 57521e47..49aa85e9 100644
--- a/include/dos_inc.h
+++ b/include/dos_inc.h
@@ -16,13 +16,17 @@
  *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  */
 
-/* $Id: dos_inc.h,v 1.52 2005-02-10 10:20:47 qbix79 Exp $ */
+/* $Id: dos_inc.h,v 1.53 2005-03-24 10:18:45 qbix79 Exp $ */
 
-#ifndef DOS_H_
-#define DOS_H_
+#ifndef DOSBOX_DOS_INC_H
+#define DOSBOX_DOS_INC_H
 
-#include <dos_system.h>
-#include <mem.h>
+#ifndef DOSBOX_DOS_SYSTEM_H
+#include "dos_system.h"
+#endif
+#ifndef DOSBOX_MEM_H
+#include "mem.h"
+#endif
 
 #ifdef _MSC_VER
 #pragma pack (1)
@@ -584,4 +588,3 @@ INLINE Bit8u RealHandle(Bit16u handle) {
 }
 
 #endif
-