diff --git a/lib/xmlparse.c b/lib/xmlparse.c
index e12853c..0655e08 100644
--- a/lib/xmlparse.c
+++ b/lib/xmlparse.c
@@ -3,6 +3,7 @@
 */
 
 #include <stddef.h>
+#include <stdint.h>
 #include <string.h>                     /* memset(), memcpy() */
 #include <assert.h>
 #include <limits.h>                     /* UINT_MAX */
@@ -722,7 +723,7 @@
   /* Process ID is 0 bits entropy if attacker has local access
    * XML_Parser address is few bits of entropy if attacker has local access */
   const unsigned long entropy =
-      gather_time_entropy() ^ getpid() ^ (unsigned long)parser;
+      gather_time_entropy() ^ getpid() ^ (uintptr_t)parser;
 
   /* Factors are 2^31-1 and 2^61-1 (Mersenne primes M31 and M61) */
   if (sizeof(unsigned long) == 4) {