Add SDK package for generating global CLI tool shims

[natemcmaster]

Infrastructure work required to enable aspnet/Universe#1126.

This is a generalization of the work added by @prafullbhosale and @seancpeters in dotnet/Scaffolding#757. It pre-generates the apphost shim for global CLI tools for win-x86, win-x64, and osx-64.

It is eventually meant to move to https://github.com/dotnet/arcade so other teams can use it.

Usage

Projects that need to bundle and sign the global CLI tool shim should add this to their .csproj file. This will include files in the .nupkg

  <Sdk Name="Microsoft.DotNet.GlobalTools.Sdk" />
 
  <PropertyGroup>
    <PackAsTool>true</PackAsTool>
    <GenerateToolShims>true</GenerateToolShims>
  </PropertyGroup>

cc @wli3

[ryanbrandenburg]

LGTM, I don't see any obvious structural problems but I also don't know the global tools stuff very well so you might want to make sure someone else reviews too.

[natemcmaster]

@pranavkm can you take a look at this too?

[pranavkm]

sad 👏

[pranavkm]

Does this need RestoreSources or does it pick the one via Directory.Build.props?

[natemcmaster]

It's set in the PreinstallBundledPackages target (see below). We can't set it here since the path will be machine-specific.

[pranavkm]

Does Razor Sdk need one of these?

[natemcmaster]

Depends. Do you expect users to reference razor as a PackageReference or only as an Sdk?

If you add this, UI tooling in VS for PackageReference will break.

[pranavkm]

Preferably both. We use it as a PackageReference in other repos in aspnet

[natemcmaster]

If NuGet UI tooling wasn't a concern, I would say you should add this to your .nuspec

  <packageTypes>
      <packageType name="Dependency" /> <!-- PackageReference usage -->
      <packageType name="MSBuildSdk" /> <!-- Sdk usage -->
  </packageTypes>

But that might be dangerous because the NuGet team is thinking of breaking packages with multiple types.

See NuGet/Home#6298 and NuGet/Home#6484 for context.