Remove unused static functions.

src/encoding.c

@@ -84,12 +84,6 @@ enum {
 
 #define mrb_usascii_str_new2 mrb_usascii_str_new_cstr
 
-static size_t
-enc_memsize(mrb_state *mrb, const void *p)
-{
-    return 0;
-}
-
 static const struct mrb_data_type encoding_data_type = {
   "encoding", 0,
 };

src/error.c

@@ -404,29 +404,6 @@ mrb_sys_fail(mrb_state *mrb, const char *mesg)
   mrb_raise(mrb, mrb->eRuntimeError_class, "%s", mesg);
 }
 
-static mrb_value
-mrb_exc_c_exception(mrb_state *mrb, mrb_value exc)
-{
-  mrb_value *argv;
-  int argc;
-
-  mrb_get_args(mrb, "*", &argv, &argc);
-  return mrb_make_exception(mrb, argc, argv);
-}
-
-static mrb_value
-mrb_exc_exception(mrb_state *mrb, mrb_value exc)
-{
-  mrb_value *argv;
-  int argc;
-  mrb_value exclass;
-
-  mrb_get_args(mrb, "*", &argv, &argc);
-  if (argc == 0) return exc;
-  exclass = mrb_obj_value(mrb_class(mrb, exc));
-  return mrb_funcall(mrb, exclass, "exception", argc, argv);
-}
-
 void
 mrb_init_exception(mrb_state *mrb)
 {

src/struct.c

@@ -31,8 +31,6 @@ mrb_value mrb_exec_recursive_paired(mrb_state *mrb, mrb_value (*func) (mrb_state
 #define mrb_long2int(n) ((int)(n))
 
 
-static mrb_value struct_alloc(mrb_state *mrb, mrb_value);
-
 static struct RClass *
 struct_class(mrb_state *mrb)
 {