def _get_platform_patterns(spec, package, src_dir):
        """
        yield platform-specific path patterns (suitable for glob
        or fn_match) from a glob-based spec (such as
        self.package_data or self.exclude_package_data)
        matching package in src_dir.
        """
        raw_patterns = itertools.chain(
            spec.get('', []),
            spec.get(package, []),
        )
        return (
            # Each pattern has to be converted to a platform-specific path
            os.path.join(src_dir, convert_path(pattern))
            for pattern in raw_patterns
        )

        yield platform-specific path patterns (suitable for glob
        or fn_match) from a glob-based spec (such as
        self.package_data or self.exclude_package_data)
        matching package in src_dir.
        
product/gradle-plugin/src/main/python/setuptools/command/build_py.py