A tentative fix for SF bug #503837 (Roeland Rengelink):

A tentative fix for SF bug #503837 (Roeland Rengelink):
type.__module__ problems (again?)

This simply initializes the __module__ local in a class statement from
the __name__ global.  I'm not 100% sure that this is the correct fix,
although it usually does the right thing.  The problem is that if the
class statement executes in a custom namespace, the __name__ global
may be taken from __builtins__, in which case it would have the value
__builtin__, or it may not exist at all (if the custom namespace also
has a custom __builtins__), in which case the class statement will
fail.

Nevertheless, unless someone finds a better solution, this is a 2.2.1
bugfix too.