bpo-38787: Add PyCFunction_CheckExact() macro for exact type checks (GH-20024)



… now that we allow subtypes of PyCFunction.

Also add PyCMethod_CheckExact() and PyCMethod_Check() for checks against the PyCMethod subtype.
diff --git a/Include/methodobject.h b/Include/methodobject.h
index 7c7362c..12e049b 100644
--- a/Include/methodobject.h
+++ b/Include/methodobject.h
@@ -13,7 +13,8 @@
 
 PyAPI_DATA(PyTypeObject) PyCFunction_Type;
 
-#define PyCFunction_Check(op) (Py_IS_TYPE(op, &PyCFunction_Type) || (PyType_IsSubtype(Py_TYPE(op), &PyCFunction_Type)))
+#define PyCFunction_CheckExact(op) Py_IS_TYPE(op, &PyCFunction_Type)
+#define PyCFunction_Check(op) PyObject_TypeCheck(op, &PyCFunction_Type)
 
 typedef PyObject *(*PyCFunction)(PyObject *, PyObject *);
 typedef PyObject *(*_PyCFunctionFast) (PyObject *, PyObject *const *, Py_ssize_t);