Okay, sorry for repeated nitpicks, but I think you can keep the visibility of sigwinch_received as static like it was as char (to avoid having it be exported for potential use by other modules, though it won't gain any optimization benefits of static, since volatile intentionally prevents any such optimizations). static volatile sig_atomic_t is kind of a mouthful, but keeps the limited visibility you want.

Also, I still don't see a review link for the patch (which limits the ability to review in context); you might need to update your checkout and regenerate the patch so the review tool can handle it.