1 files changed, 1 insertions, 0 deletions
diff --git a/inits.c b/inits.c
index f702e306b0..8c230c6df0 100644
--- a/inits.c
+++ b/inits.c
@@ -51,6 +51,7 @@ rb_call_inits(void)
     CALL(marshal);
     CALL(Range);
     CALL(IO);
+    CALL(IO_Buffer)
     CALL(Dir);
     CALL(Time);
     CALL(Random);