Here's the quote from mxSetup.py:

    # distutils changed a lot in Python 2.7 due to many
    # distutils.sysconfig APIs having been moved to the new
    # (top-level) sysconfig module.
    from sysconfig import \
         get_config_h_filename, parse_config_h, get_path, \
         get_config_vars, get_python_version, get_platform

    # This API was moved from distutils.sysconfig to distutils.ccompiler
    # in Python 2.7
    from distutils.ccompiler import customize_compiler

So in 2.7 the function was moved from sysconfig to ccompiler (where it belongs), and now you're reverting the change in the third dot release.