1 files changed, 2 insertions, 0 deletions
diff --git a/src/gc.c b/src/gc.c
index c0d4e1599..1468dd994 100644
--- a/src/gc.c
+++ b/src/gc.c
@@ -545,6 +545,8 @@ obj_free(mrb_state *mrb, struct RBasic *obj)
   obj->tt = MRB_TT_FREE;
 }
 
+#include <stdio.h>
+
 static void
 root_scan_phase(mrb_state *mrb)
 {