Patch for copy_to_build_dir

req.py

    def copy_to_build_dir(self, req_to_install):
        target_dir = req_to_install.editable and self.src_dir or self.build_dir
        logger.info("Copying %s to %s" % (req_to_install.name, target_dir))
        dest = os.path.join(target_dir, req_to_install.name)
        copytree(req_to_install.source_dir, dest)
        call_subprocess(["python", "%s/setup.py" % dest, "clean"],
                        cwd=dest)