Include stdarg.h in mkdtemp for va_list.
diff --git a/regress/mkdtemp.c b/regress/mkdtemp.c
index 8c7d2e2..bed8861 100644
--- a/regress/mkdtemp.c
+++ b/regress/mkdtemp.c
@@ -19,6 +19,7 @@
 #include "includes.h"
 
 #include <limits.h>
+#include <stdarg.h>
 #include <stdio.h>
 #include <stdlib.h>