diff --git a/src/charsets.c b/src/charsets.c
index da9485308..f2e69e0b2 100644
--- a/src/charsets.c
+++ b/src/charsets.c
@@ -27,6 +27,8 @@
 
 #include <iconv.h>
 
+#include <mhl/string.h>
+
 #include "global.h"
 #include "charsets.h"