Allow building net471 target without Windows

[lostmsu]

No description provided.

[MoFtZ]

QUESTION: Microsoft.NETFramework.ReferenceAssemblies is an interesting Nuget package - first time I have heard of it. Should we be using the more specific Microsoft.NETFramework.ReferenceAssemblies.net471?

Also, if we plan on using this Nuget package, we should apply it to all the other locations in ILGPU too. e.g. unit test projects.

[lostmsu]

For the reference, official doc.

AFAIK Microsoft recommends using the "meta-package", however, I used specific version too without any issues.

Only the projects, that target .NET Framework need this. It just allows .NET SDK to build net4xx target on non-Windows OS and on Windows OS where SDK targeting pack is not installed.

I noticed now, that test projects actually have net471 too, but only for GitHub actions. I don't think this change is needed for GitHub actions, because unless you want to add Mono to your test matrix, there's no point in building net471 test target on non-Windows.

Actually, there's one advantage to adding this package to tests: building with .NET SDK would be possible without installing targeting pack workloads with Visual Studio. However, in Visual Studio itself it would not be enough unfortunately, until Microsoft fixes corresponding issue.

[lostmsu]

@MoFtZ do you want me to rebase this?

[MoFtZ]

This is unlikely to cause conflicts, so no need to rebase. Just wait for @m4rs-mt to review.

[m4rs-mt]

Looks also good to me 👍 Thanks a lot for this simplification!