`nvptx install` fails on Windows

[bheisler]

If I run nvptx install in Git Bash, this is the result:

$ nvptx install
download: https://s3-ap-northeast-1.amazonaws.com/rust-accel/rustc-1.28.0-dev-x86_64-unknown-linux-gnu.tar.xz
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 51.9M  100 51.9M    0     0  1833k      0  0:00:29  0:00:29 --:--:-- 1710k
expand: rustc-1.28.0-dev-x86_64-unknown-linux-gnu
Error: OtherError { step: Install, comment: "Unknown IO Error", error: Os { code: 2, kind: NotFound, message: "The system cannot find the file specified." } }

I'm not sure which file it can't find. Also, the x86_64-unknown-linux-gnu build is wrong for Windows.

[termoshtt]

I totally forget Windows support. We need to start with building rustc.

[mrbianchi]

same problem :/