Linking embedded interops in package reference

[nkolev92]

In the packages.config case, when adding a package NuGet would walk through the compatible references and call VSLangProj.References.Add(assemblyPath).

There, project system would figure out if it's an interop assembly and set true.

Now in package reference, we don't add the references through project system, so interop dlls are referenced the same way as the others instead of linked.

Example assets file:

      "TestR/1.2.5": {
        "type": "package",
        "dependencies": {
          "Newtonsoft.Json": "10.0.2"
        },
        "compile": {
          "lib/net452/Interop.UIAutomationClient.dll": {},
          "lib/net452/TestR.dll": {}
        },
        "runtime": {
          "lib/net452/Interop.UIAutomationClient.dll": {},
          "lib/net452/TestR.dll": {}
        }
      }

We'd prefer to solve this linking without impacting package authors.

We can't really rely on PS in VS because then restoring from commandline would be different from VS.

One idea would be to update the NuGet Build targets to do a sniff test for dlls that need to be linked.

Related to NuGet/Home#2365

//cc
@rrelyea @natidea @davkean @tmeschter

[nkolev92]

We have decided to move this responsibility to the package author.