diff --git a/lib/dns/tests/rbt_test.c b/lib/dns/tests/rbt_test.c
index 960f24361d..4f223e03c1 100644
--- a/lib/dns/tests/rbt_test.c
+++ b/lib/dns/tests/rbt_test.c
@@ -26,6 +26,10 @@
 #include <unistd.h>
 #include <sys/mman.h>
 
+#ifdef HAVE_INTTYPES_H
+#include <inttypes.h> /* uintptr_t */
+#endif
+
 #include <dns/rbt.h>
 #include <dns/fixedname.h>
 #include <dns/result.h>