diff --git a/ghc/includes/RtsAPI.h b/ghc/includes/RtsAPI.h
index b6fd0f1afc016dcb1f3b0edea63d517921fd198d..1eb0d279010dd9779427bb6d40b1eae33001b1eb 100644
--- a/ghc/includes/RtsAPI.h
+++ b/ghc/includes/RtsAPI.h
@@ -1,5 +1,5 @@
 /* ----------------------------------------------------------------------------
- * $Id: RtsAPI.h,v 1.13 2000/04/26 09:29:37 simonmar Exp $
+ * $Id: RtsAPI.h,v 1.14 2000/06/15 13:16:16 daan Exp $
  *
  * (c) The GHC Team, 1998-1999
  *
@@ -10,6 +10,18 @@
 #ifndef RTSAPI_H
 #define RTSAPI_H
 
+/* Make this compilable with Visual C++ */
+#ifndef HAVE_INT64
+#define HAVE_INT64
+#ifdef _MSC_VER 
+typedef __int64            int64;
+typedef unsigned __int64   nat64;
+#else
+typedef long long          int64;
+typedef unsigned long long nat64;
+#endif
+#endif
+
 /*
  * Running the scheduler
  */
@@ -40,12 +52,12 @@ HaskellObj   rts_mkInt        ( int i );
 HaskellObj   rts_mkInt8       ( int i );
 HaskellObj   rts_mkInt16      ( int i );
 HaskellObj   rts_mkInt32      ( int i );
-HaskellObj   rts_mkInt64      ( long long i );
+HaskellObj   rts_mkInt64      ( int64 i );
 HaskellObj   rts_mkWord       ( unsigned int w );
 HaskellObj   rts_mkWord8      ( unsigned int w );
 HaskellObj   rts_mkWord16     ( unsigned int w );
 HaskellObj   rts_mkWord32     ( unsigned int w );
-HaskellObj   rts_mkWord64     ( unsigned long long w );
+HaskellObj   rts_mkWord64     ( nat64 w );
 HaskellObj   rts_mkFloat      ( float f );
 HaskellObj   rts_mkDouble     ( double f );
 HaskellObj   rts_mkStablePtr  ( StgStablePtr s );