errno.c: use `mrb_fixnum_p()` instead of `mrb_type()`.
@@ -20,7 +20,7 @@ mrb_sce_init(mrb_state *mrb, mrb_value self)
argc = mrb_get_args(mrb, "o|i", &m, &n);
if (argc == 1) {
- if (mrb_type(m) == MRB_TT_FIXNUM) {
+ if (mrb_fixnum_p(m)) {
n = mrb_fixnum(m);
m = mrb_nil_value();
} else {
