sources:
  rust-1.28.0-i686-unknown-linux-gnu.tar.xz: 9f2d0457eedf0c9c38fa3c16d19b3a112338cea6
  rust-1.28.0-x86_64-unknown-linux-gnu.tar.xz: ed58f73ef18907ffd3c3157087bebfb88f4449a0
  rustc-1.29.1-src.tar.xz: 3c5ed672a33acf182f2d21c41db03f87a56e00ad