The ``structmember.h`` header is deprecated. Its non-deprecated contents are
now available just by including ``Python.h``, with a ``Py_`` prefix added if
it was missing. (Deprecated contents are :c:macro:`T_OBJECT`,
:c:macro:`T_NONE`, and no-op flags.) Patch by Petr Viktorin, based on
earlier work by Alexander Belopolsky and Matthias Braun.
