[Python-Dev] Add a frozendict builtin type

[Victor Stinner]

> A builtin frozendict type "compatible" with the PyDict C API is very
> convinient for pysandbox because using this type for core features
> like builtins requires very few modification. For example, use
> frozendict for __builtins__ only requires to modify 3 lines in
> frameobject.c.

See the frozendict_builtins.patch attached to the issue #14162. Last version:
http://bugs.python.org/file24690/frozendict_builtins.patch

Victor