Render tempita templates before calling cythonize

def maybe_cythonize(extensions, *args, **kwargs):
    """
    Render tempita templates before calling cythonize
    """
    if len(sys.argv) > 1 and 'clean' in sys.argv:
        # Avoid running cythonize on `python setup.py clean`
        # See https://github.com/cython/cython/issues/1495
        return extensions
    if not cython:
        # Avoid trying to look up numpy when installing from sdist
        # https://github.com/pandas-dev/pandas/issues/25193
        # TODO: See if this can be removed after pyproject.toml added.
        return extensions

    numpy_incl = pkg_resources.resource_filename('numpy', 'core/include')
    # TODO: Is this really necessary here?
    for ext in extensions:
        if (hasattr(ext, 'include_dirs') and
                numpy_incl not in ext.include_dirs):
            ext.include_dirs.append(numpy_incl)

    build_ext.render_templates(_pxifiles)
    return cythonize(extensions, *args, **kwargs)