diff --git a/util/cairo-script/csi-replay.c b/util/cairo-script/csi-replay.c
index 4e0b6065f..732d0ea5b 100644
--- a/util/cairo-script/csi-replay.c
+++ b/util/cairo-script/csi-replay.c
@@ -3,6 +3,7 @@
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 
 static const cairo_user_data_key_t _key;