1 files changed, 1 insertions, 0 deletions
diff --git a/encoding.c b/encoding.c
index e0f2bc9154..a6d0fcd3d7 100644
--- a/encoding.c
+++ b/encoding.c
@@ -16,6 +16,7 @@
 #ifdef HAVE_LANGINFO_H
 #include <langinfo.h>
 #endif
+#include "ruby/util.h"
 
 static ID id_encoding, id_base_encoding;
 VALUE rb_cEncoding;