message: Add license section to the readme
  Just in case
diff: @@ -55,3 +55,20 @@ See [env_vars.md](docs/env_vars.md) for all env vars used by rustc_codegen_crane
  `llvm_asm!` will remain unimplemented forever. `asm!` doesn't yet support reg classes. You
  have to specify specific registers instead.
  * SIMD ([tracked here](https://github.com/bjorn3/rustc_codegen_cranelift/issues/171), some basic things work)
  +
  +## License
  +
  +Licensed under either of
  +
  + * Apache License, Version 2.0 ([LICENSE-APACHE](LICENSE-APACHE) or
  + http://www.apache.org/licenses/LICENSE-2.0)
  + * MIT license ([LICENSE-MIT](LICENSE-MIT) or
  + http://opensource.org/licenses/MIT)
  +
  +at your option.
  +
  +### Contribution
  +
  +Unless you explicitly state otherwise, any contribution intentionally submitted
  +for inclusion in the work by you shall be dual licensed as above, without any
  +additional terms or conditions.
  