Message 339079 - Python tracker

When Python is built in debug mode, PyObject gets 2 new fields: _ob_prev and _ob_next. These fields change the offset of following fields in the PyObject structure and so breaks the ABI.

I propose to modify the debug build (Py_DEBUG) to not imply Py_TRACE_REFS anymore. Antoine Pitrou proposed this idea when the C API was discussed to get a stable ABI.

Another more radical idea is to completely remove Py_TRACE_REFS special build.