Index: generic/nsf.c
===================================================================
diff -u -rf92df553a299a7ef91e1d53656282e23441f8c87 -r6ebbaeeee26137ccd4aaa4d6044de2c76adf7f98
--- generic/nsf.c	(.../nsf.c)	(revision f92df553a299a7ef91e1d53656282e23441f8c87)
+++ generic/nsf.c	(.../nsf.c)	(revision 6ebbaeeee26137ccd4aaa4d6044de2c76adf7f98)
@@ -6750,8 +6750,8 @@
      * Avoid hijacking a namespace with different client data
      */
     if (nsPtr->deleteProc || nsPtr->clientData) {
-      Tcl_Panic("Namespace '%s' exists already with delProc 0x%x and clientData %p; "
-                "Can only convert a plain Tcl namespace into an NSF namespace, my delete proc 0x%x",
+      Tcl_Panic("Namespace '%s' exists already with delProc 0x%" PRIxPTR " and clientData %p; "
+                "Can only convert a plain Tcl namespace into an NSF namespace, my delete proc 0x%" PRIxPTR,
                 name, PTR2UINT(nsPtr->deleteProc), nsPtr->clientData, PTR2UINT(NSNamespaceDeleteProc));
     }
 
Index: generic/nsfInt.h
===================================================================
diff -u -rb9bcc40ab502329b1e7bc4ed6602adf7bd5e614d -r6ebbaeeee26137ccd4aaa4d6044de2c76adf7f98
--- generic/nsfInt.h	(.../nsfInt.h)	(revision b9bcc40ab502329b1e7bc4ed6602adf7bd5e614d)
+++ generic/nsfInt.h	(.../nsfInt.h)	(revision 6ebbaeeee26137ccd4aaa4d6044de2c76adf7f98)
@@ -4,9 +4,9 @@
  *      Declarations of the internally used API Functions of the Next
  *      Scripting Framework.
  *
- *  Copyright (C) 1999-2017 Gustaf Neumann (a, b)
+ *  Copyright (C) 1999-2018 Gustaf Neumann (a, b)
  *  Copyright (C) 1999-2007 Uwe Zdun (a, b)
- *  Copyright (C) 2011-2017 Stefan Sobernig (b)
+ *  Copyright (C) 2011-2018 Stefan Sobernig (b)
  *
  * (a) University of Essen
  *     Specification of Software Systems
@@ -46,9 +46,21 @@
 #ifndef _nsf_int_h_
 #define _nsf_int_h_
 
-#if defined(HAVE_STDINT_H)
-# define HAVE_INTPTR_T
-# define HAVE_UINTPTR_T
+#if !defined(HAVE_STDINT_H)
+# if !defined(__PRIPTR_PREFIX)
+#  if defined(_LP64) || defined(_I32LPx) || defined(HAVE_64BIT) || defined(_WIN64) || defined(_WIN32)
+#   if defined(_WIN32)
+#    define __PRIPTR_PREFIX "ll"
+#   else
+#    define __PRIPTR_PREFIX "l"
+#   endif
+#  else
+#   define __PRIPTR_PREFIX
+#  endif
+# endif
+# ifndef PRIxPTR
+#  define PRIxPTR    __PRIPTR_PREFIX "x"
+# endif
 #endif
 
 /*