E.g. libc tests on a wide variety [on travis](https://github.com/rust-lang-nursery/libc/blob/master/.travis.yml), via [qemu](https://github.com/rust-lang-nursery/libc/blob/8531cc11e196b7ae9072ae7b384a930ff7b00dfb/ci/run-travis.sh#L74). cc #55.
