又学到一招，GitHub提供某个pull的patch下载，构造链接方式为 https://patch-diff.githubusercontent.com/raw/username/reponame/pull/ID.patch

比如这个pull的补丁文件下载链接为https://patch-diff.githubusercontent.com/raw/iwestlin/lab/pull/1.patch

（来自 https://github.com/iwestlin/lab/pull/1.patch的重定向