In the beta 1 release we added a utility function for extension module
authors, to use when testing their module for support in multiple
interpreters or under a per-interpreter GIL.  The name of that function has
changed from ``allowing_all_extensions`` to
``_incompatible_extension_module_restrictions``.  The default for the
"disable_check" argument has change from ``True`` to ``False``, to better
match the new function name.