[Distutils] warning about potential problem for wheels

[Laura Creighton]

(note, I currently don't have mail delivery on for distutils.  I could
change this, but right now I don't think I have a lot to contribute.
This is just a warning).

If you have old windows hardware, which does not support SSE2, and
windows 7, you can build your own python 3.5.  This will work. But
wheels won't, you will need to build them from source as well.
see: http://bugs.python.org/issue25361

This means that wheels could start failing.  It would be good if
the wheels themselves could detect this problem and protest in a
reasonable fashion, but I have no idea if this is possible.  In any
case, I thought you needed to know.

Laura