Iain's commits to trunk (11) that I could not apply to gcc-10:

- https://github.com/iains/gcc-darwin-arm64/commit/1cf917fa3baa8b40ae1e223a2b820f2c3222753d


Tests, so not really crucial:

- https://github.com/iains/gcc-darwin-arm64/commit/8553ec86bc0ff83a8430a769548bcbce77b1a285

