Add script to build many glibc configurations

[Joseph Myers]

On Mon, 14 Nov 2016, Mike Frysinger wrote:

> > +class Context:
> 
> please no old style classes.  all of them should inherit object.
> 	class Context(object):

There's no such thing as an old-style class in Python 3 (and this script 
requires 3.5 or later); inheritance from object happens by default.

-- 
Joseph S. Myers
joseph@codesourcery.com