diff --git a/acinclude.m4 b/acinclude.m4
index f0a8266b..9ea0d7a2 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -305,7 +305,7 @@ AC_SUBST(ALSA_LIBS)
 
 AH_TOP([
 /*
- *  Copyright (C) 2002-2003  The DOSBox Team
+ *  Copyright (C) 2002-2004  The DOSBox Team
  *
  *  This program is free software; you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -331,4 +331,49 @@ AH_BOTTOM([#if C_HAS_ATTRIBUTE
 #define GCC_ATTRIBUTE(x) /* attribute not supported */
 #endif])
 
+AH_BOTTOM([
+typedef         double     Real64;
 
+#if SIZEOF_UNSIGNED_CHAR != 1
+#  error "sizeof (unsigned char) != 1"
+#else
+  typedef unsigned char Bit8u;
+  typedef   signed char Bit8s;
+#endif
+
+#if SIZEOF_UNSIGNED_SHORT != 2
+#  error "sizeof (unsigned short) != 2"
+#else
+  typedef unsigned short Bit16u;
+  typedef   signed short Bit16s;
+#endif
+
+#if SIZEOF_UNSIGNED_INT == 4
+  typedef unsigned int Bit32u;
+  typedef   signed int Bit32s;
+#elif SIZEOF_UNSIGNED_LONG == 4
+  typedef unsigned long Bit32u;
+  typedef   signed long Bit32s;
+#else
+#  error "can't find sizeof(type) of 4 bytes!"
+#endif
+
+#if SIZEOF_UNSIGNED_LONG == 8
+  typedef unsigned long Bit64u;
+  typedef   signed long Bit64s;
+#elif SIZEOF_UNSIGNED_LONG_LONG == 8
+  typedef unsigned long long Bit64u;
+  typedef   signed long long Bit64s;
+#else
+#  error "can't find data type of 8 bytes"
+#endif
+
+#if SIZEOF_INT_P == 4
+  typedef Bit32u Bitu;
+  typedef Bit32s Bits;
+ #else
+  typedef Bit64u Bitu;
+  typedef Bit64s Bits;
+ #endif
+
+])
\ No newline at end of file
diff --git a/configure.in b/configure.in
index 657a3015..0cc5ca58 100644
--- a/configure.in
+++ b/configure.in
@@ -35,7 +35,12 @@ AC_C_CONST
 AC_C_INLINE
 AC_TYPE_SIZE_T
 AC_STRUCT_TM
-
+AC_CHECK_SIZEOF(unsigned char)
+AC_CHECK_SIZEOF(unsigned short)
+AC_CHECK_SIZEOF(unsigned int)
+AC_CHECK_SIZEOF(unsigned long)
+AC_CHECK_SIZEOF(unsigned long long)
+AC_CHECK_SIZEOF(int *)
 
 AC_MSG_CHECKING(if environ can be included)
 AC_TRY_LINK([#include <unistd.h>
diff --git a/include/dosbox.h b/include/dosbox.h
index a1061790..afb93bb4 100644
--- a/include/dosbox.h
+++ b/include/dosbox.h
@@ -24,25 +24,6 @@ void E_Exit(char * message,...);
 void MSG_Add(const char*,const char*); //add messages to the internal langaugefile
 const char* MSG_Get(char const *);         //get messages from the internal langaugafile
 
-/* The internal types */
-typedef  unsigned char     Bit8u;
-typedef    signed char     Bit8s;
-typedef unsigned short     Bit16u;
-typedef   signed short     Bit16s;
-typedef  unsigned long     Bit32u;
-typedef    signed long     Bit32s;
-typedef         double     Real64;
-#if defined(_MSC_VER)
-typedef unsigned __int64   Bit64u;
-typedef   signed __int64   Bit64s;
-#else
-typedef unsigned long long Bit64u;
-typedef   signed long long Bit64s;
-#endif
-
-typedef unsigned int Bitu;
-typedef signed int Bits;
-
 #include <stddef.h>
 #include "config.h"
 
diff --git a/src/platform/visualc/config.h b/src/platform/visualc/config.h
index c3260199..78ccbefc 100644
--- a/src/platform/visualc/config.h
+++ b/src/platform/visualc/config.h
@@ -39,3 +39,17 @@
 #define ENVIRON_LINKED 1
 
 #define GCC_ATTRIBUTE(x) /* attribute not supported */
+
+typedef         double		Real64;
+/* The internal types */
+typedef  unsigned char		Bit8u;
+typedef    signed char		Bit8s;
+typedef unsigned short		Bit16u;
+typedef   signed short		Bit16s;
+typedef  unsigned long		Bit32u;
+typedef    signed long		Bit32s;
+typedef unsigned __int64	Bit64u;
+typedef   signed __int64	Bit64s;
+typedef unsigned int		Bitu;
+typedef signed int			Bits;
+