Issue #19437: Fix PyImport_ImportModuleLevelObject(), handle
PyUnicode_Substring() failure (ex: MemoryError)
Issue #19437: Fix PyCData_GetContainer() of ctypes, handle PyDict_New() failure
Issue #19437: Fix GetKeepedObjects() of ctypes, handle PyCData_GetContainer()
failure
Issue #19437: Fix ctypes, handle PyCData_GetContainer() and GetKeepedObjects()
failures
Don't use deprecated function PyUnicode_GET_SIZE()

Replace it with PyUnicode_GET_LENGTH() or PyUnicode_AsUnicodeAndSize()
Close #17828: better handling of codec errors

- output type errors now redirect users to the type-neutral
  convenience functions in the codecs module
- stateless errors that occur during encoding and decoding
  will now be automatically wrapped in exceptions that give
  the name of the codec involved
Issue #17839: mention base64 change in What's New
asyncio: Temporary fix by Victor Stinner for issue 19566.
removed Enum.__eq__ as it added nothing
asyncio: Fix from Anthony Baire for CPython issue 19566 (replaces earlier fix).
Issue #19437: Fix fold_unaryops_on_constants() of the peephole optimizer, clear
the exception when PyList_Append() fails
Issue #19437: Use an identifier for "__name__" string in pickle to improve
error handling

The following code didn't handle correctly the failure of
PyUnicode_InternFromString("__name__").

if (newobj_str == NULL) {
    newobj_str = PyUnicode_InternFromString("__newobj__");
    name_str = PyUnicode_InternFromString("__name__");
    if (newobj_str == NULL || name_str == NULL)
        return -1;
}
Issue #19437: Fix array.buffer_info(), handle PyLong_FromVoidPtr() and
PyLong_FromLong() failure
Issue #17828: va_start() must be accompanied by va_end()
CID 1128793: Missing varargs init or cleanup (VARARGS)
Issue #17828: _PyObject_GetDictPtr() may return NULL instead of a PyObject**
CID 1128792: Dereference null return value (NULL_RETURNS)
merge
asyncio: Relax timing requirement. Fixes issue 19579.
adjust style
fix refleaks