Would it be possible to support lzma-rs as an alternative to liblzma-sys?

https://github.com/Portable-Network-Archive/liblzma-rs has a single maintainer and a C submodule, which makes it hard for us to review and trust the crate (#288). lzma-rs is written entirely in safe Rust, which makes it much easier for us to verify, and it also avoids another C dependencies and its (static) linking workarounds.