diff --git a/lib/smap.c b/lib/smap.c
index 54b339f0e..0d7573305 100644
--- a/lib/smap.c
+++ b/lib/smap.c
@@ -15,6 +15,8 @@
 #include <config.h>
 #include "smap.h"
 
+#include <strings.h>
+
 #include "hash.h"
 #include "json.h"