diff --git a/support/support_wait_for_thread_exit.c b/support/support_wait_for_thread_exit.c
index 75d3b8009e..449f1fc598 100644
--- a/support/support_wait_for_thread_exit.c
+++ b/support/support_wait_for_thread_exit.c
@@ -18,6 +18,7 @@
 
 #include <dirent.h>
 #include <errno.h>
+#include <stdlib.h>
 #include <string.h>
 #include <support/check.h>
 #include <support/support.h>