diff --git a/mrblib/init_mrblib.c b/mrblib/init_mrblib.c
index a845489f56..72355e3eb2 100644
--- a/mrblib/init_mrblib.c
+++ b/mrblib/init_mrblib.c
@@ -11,7 +11,6 @@ mrb_init_mrblib(mrb_state *mrb)
 {
   int n = mrb_read_irep(mrb, mrblib_irep);
 
-  extern mrb_value mrb_top_self(mrb_state *mrb);
   mrb_run(mrb, mrb_proc_new(mrb, mrb->irep[n]), mrb_top_self(mrb));
 }
 
diff --git a/src/struct.c b/src/struct.c
index a5ffe64536..a1ad2e1c0f 100644
--- a/src/struct.c
+++ b/src/struct.c
@@ -11,7 +11,6 @@
 #include "mruby/struct.h"
 #include "mruby/array.h"
 #include <stdarg.h>
-//#include "defines.h"
 
 #ifdef ENABLE_REGEXP
 #include "encoding.h"
@@ -20,8 +19,6 @@
 #include "mruby/string.h"
 #include "mruby/class.h"
 #include "mruby/variable.h"
-//#include "defines.h"
-#define mrb_long2int(n) ((int)(n))
 
 
 static struct RClass *