There's now a new structmember code, T_OBJECT_EX, which is used for
all __slot__ variables (except __weakref__, which has special behavior
anyway).  This new code raises AttributeError when the variable is
NULL rather than converting NULL to None.

compatibility, this required all places where an array of "struct
memberlist" structures was declared that is referenced from a type's
tp_members slot to change the type of the structure to PyMemberDef;
"struct memberlist" is now only used by old code that still calls
PyMember_Get/Set.  The code in PyObject_GenericGetAttr/SetAttr now
calls the new APIs PyMember_GetOne/SetOne, which take a PyMemberDef
argument.

As examples, I added actual docstrings to the attributes of a few
types: file, complex, instance method, super, and xxsubtype.spamlist.

Also converted the symtable to new style getattr.

Renamed the 'readonly' field to 'flags' and defined some new flag
bits: READ_RESTRICTED and WRITE_RESTRICTED, as well as a shortcut
RESTRICTED that means both.

SF patch http://sourceforge.net/patch/?func=detailpatch&patch_id=103453&group_id=5470
PyMember_Set of T_CHAR always raises exception.
Unfortunately, this is a use of a C API function that Python itself never makes, so
there's no .py test I can check in to verify this stays fixed.  But the fault in the
code is obvious, and Dave Cole's patch just as obviously fixes it.

This should match the situation in the 1.6b1 tree.

declarations yet, those come later.