Building ghc on Windows with msys2

[Herbert Valerio Riedel]

On 2014-10-13 at 10:57:10 +0200, Simon Peyton Jones wrote:
> I think the potential difficulty is (1).  Maybe they take it down (e.g. they move on to version X so they take down old version Y).
>
> An alternative would be to stash a copy somewhere on GHC’s main web
> server, and wget that.  I’d be more comfortable doing that; less
> dependence on others.

I guess storing a copy somewhere on https://ghc.haskell.org/ should be
ok (I'm hoping Austin may weigh in wrt CDN-related considerations). I'd
suggest using it as a fallback location though. I.e. try downloading
from the official upstream location, and if that fails (either due to
I/O errors and/or unexpected checksum), fallback to using our locally
mirrored copy. However, we may need to take into account license issues,
such as hosting the source-code as well, if we host binary distributions
depending on the licenses involved (I'm not sure if this was ever
considered for ghc-tarballs.git to begin with)

Cheers,
  hvr