Thanks for the update. Well, that comment and patch are just copied from the current [`zlib` formula in `homebrew/dupes`](https://github.com/Homebrew/homebrew-dupes/blob/master/zlib.rb)

I couldn't find in https://github.com/Homebrew/homebrew-dupes/pull/228 a specific link, but did find the following open pull request: https://github.com/madler/zlib/pull/54. Will amend this commit, but it should probably be added to the `zlib` formula as well. I have no opinion on the correctness of the patch.