Rename _Py_identifier to _Py_IDENTIFIER.
diff --git a/Modules/itertoolsmodule.c b/Modules/itertoolsmodule.c
index 4f81fe2..63f199b 100644
--- a/Modules/itertoolsmodule.c
+++ b/Modules/itertoolsmodule.c
@@ -654,7 +654,7 @@
         copyable = it;
     PyTuple_SET_ITEM(result, 0, copyable);
     for (i=1 ; i<n ; i++) {
-        _Py_identifier(__copy__);
+        _Py_IDENTIFIER(__copy__);
 
         copyable = _PyObject_CallMethodId(copyable, &PyId___copy__, NULL);
         if (copyable == NULL) {