bootstrap dist command is trying to run unix date command on a windows system

[onur]

This issue is currently blocking me to upgrade rustc on docs.rs.

When I try to run python x.py dist, bootstrap is failing with following output:

Dist rustc stage2 (i686-pc-windows-msvc)


failed to execute command: "date" "+%B %Y"
error: The system cannot find the file specified. (os error 2)


failed to run: c:\rust\build\bootstrap\debug\bootstrap --config debian\config-win32.toml dist
Build completed unsuccessfully in 0:01:24

Windows doesn't have a date executable. I tried to copy MSYS's date (along with all dependencies) to $PATH, it worked for x86_64-pc-windows-msvc but still failing on i686-pc-windows-msvc.

date command is being called in src/bootstrap/dist.rs#L450-L451. It should be fairly easy to replace this with time crate.

I'll take this!