I'd like a second opinion about whether it's a good idea to commit the
attached patch, which moves abc._Abstract into object. Its effect is to
speed

  ./python.exe -m timeit -s 'import abc' -s 'class Foo(object):
__metaclass__=abc.ABCMeta' 'Foo()'

up from 2.5us to 0.201us. For comparison:

  $ ./python.exe -m timeit -s 'import abc' -s 'class Foo(object): pass'
'Foo()'
  10000000 loops, best of 3: 0.203 usec per loop
  $ ./python.exe -m timeit -s 'import abc' -s 'class Foo(object):' -s '
 def __new__(cls): return super(Foo, cls).__new__(cls)' 'Foo()'
  1000000 loops, best of 3: 1.18 usec per loop
  $ ./python.exe -m timeit -s 'import abc' -s 'from decimal import
Decimal' 'Decimal()'
  100000 loops, best of 3: 9.51 usec per loop


After this patch, the only slowdown I can find is an extra .5us in
isinstance, so I think it'll be time to close this bug.