1 files changed, 1 insertions, 0 deletions
diff --git a/pack.c b/pack.c
index 45b816a590..3f2955e4cc 100644
--- a/pack.c
+++ b/pack.c
@@ -9,6 +9,7 @@
 
 **********************************************************************/
 
+#include "ruby/encoding.h"
 #include "internal.h"
 #include <sys/types.h>
 #include <ctype.h>