diff --git a/include/SWI-Prolog.h b/include/SWI-Prolog.h
index f9a05d7a4..29107330c 100755
--- a/include/SWI-Prolog.h
+++ b/include/SWI-Prolog.h
@@ -111,12 +111,15 @@ stuff.
 
 
 #ifdef __WINDOWS__
+#ifndef INT64_T_DEFINED
+#define INT64_T_DEFINED 1
 typedef __int64 int64_t;
 typedef unsigned __int64 uint64_t;
-#if (_MSC_VER < 1300)
+#if (_MSC_VER < 1300) && !defined(__MINGW32__)
 typedef long intptr_t;
 typedef unsigned long uintptr_t;
 #endif
+#endif
 #else
 #include <inttypes.h>			/* more portable than stdint.h */
 #endif
@@ -131,12 +134,7 @@ typedef uintptr_t    functor_t;
 typedef int     (*PL_agc_hook_t)(atom_t);
 typedef unsigned long	foreign_t;	/* return type of foreign functions */
 typedef wchar_t pl_wchar_t;             /* wide character support */
-#ifdef WIN32
-typedef __int64 int64_t;
-typedef unsigned __int64 uint64_t;
-#else
 #include <inttypes.h>			/* more portable than stdint.h */
-#endif
 #if  !defined(_MSC_VER) 
 typedef uintptr_t	PL_fid_t;	/* opaque foreign context handle */
 #endif
@@ -663,7 +661,6 @@ PL_EXPORT(int)	 	PL_foreign_control(control_t);
 PL_EXPORT(intptr_t)	PL_foreign_context(control_t);
 PL_EXPORT(void *)	PL_foreign_context_address(control_t);
 
-
 /*  SWI stream info */
 PL_EXPORT(void)         PL_YAP_InitSWIIO(functor_t f, 
 					 void *gc,
diff --git a/include/SWI-Stream.h b/include/SWI-Stream.h
index 9e5b1ad21..542503576 100755
--- a/include/SWI-Stream.h
+++ b/include/SWI-Stream.h
@@ -46,12 +46,16 @@
 #include <wchar.h>
 #include <stddef.h>
 #ifdef __WINDOWS__
+#ifndef INT64_T_DEFINED
+#define INT64_T_DEFINED 1
 typedef __int64 int64_t;
+typedef unsigned __int64 uint64_t;
 #if (_MSC_VER < 1300) && !defined(__MINGW32__)
 typedef long intptr_t;
 typedef unsigned long uintptr_t;
 typedef intptr_t ssize_t;		/* signed version of size_t */
 #endif
+#endif
 #else
 #include <unistd.h>
 #include <inttypes.h>			/* more portable than stdint.h */
@@ -207,7 +211,7 @@ PL_EXPORT(IOSTREAM *)	S__getiob(void);	/* get DLL's __iob[] address */
 
 PL_EXPORT_DATA(IOFUNCTIONS)  Sfilefunctions;	/* OS file functions */
 PL_EXPORT_DATA(int)	     Slinesize;		/* Sgets() linesize */
-#if defined(__CYGWIN__) && !defined(PL_KERNEL)
+#if (defined(__CYGWIN__) || defined(__MINGW32__)) && !defined(PL_KERNEL)
 #define S__iob S__getiob()
 #else
 PL_EXPORT_DATA(IOSTREAM)    S__iob[3];		/* Libs standard streams */