diff --git a/test/threads/hb-subset-threads.cc b/test/threads/hb-subset-threads.cc
index 9d86d8d51..f0e4b7e2a 100644
--- a/test/threads/hb-subset-threads.cc
+++ b/test/threads/hb-subset-threads.cc
@@ -1,4 +1,6 @@
 #include <cassert>
+#include <cstdio>
+#include <cstdlib>
 #include <cstring>
 #include <thread>
 #include <condition_variable>