diff --git a/tcl.c b/tcl.c
index 1dbdad4..acc8d45 100644
--- a/tcl.c
+++ b/tcl.c
@@ -2,6 +2,9 @@
  *	Copyright (c) 1999-2003 Smithsonian Astrophysical Observatory
  */
 
+//declares uintptr_t
+#include<stdint.h>
+
 #include <xpap.h>
 
 #if HAVE_TCL