Proposed patches replaced idiomatic code

    Py_DECREF(ptr);
    ptr = new_value;

to "Py_REPLACE(ptr, new_value);" which is expanded to

    {
        PyObject *__tmp__ = ptr;
        ptr = new_value;
        Py_DECREF(__tmp__);
    }

(and same for Py_XDECREF -> Py_XREPLACE).

Victor proposed large patch for issue16447, but this issue was closed after fixing particular bug. Here are updated patches, which Py_REPLACE/Py_XREPLACE macros for cleaner code. They are also generated automatically by the Coccinelle tool (http://coccinelle.lip6.fr/):

spatch --in-place --sp-file py_replace.spatch --dir .

Patch for every version contains about 50 replaces in about 21-24 files.