title: nuget pack a PCL for net451 and dnxcore50
body: <p>I have a PCL project that targets .NET Framework 4.5 + ASP.NET Core 5.0. That means PCL Profile 75 according to the contents of the .csproj file.</p>
  
  <p>I added a basic .nuspec file with the same name as the .csproj file.</p>
  
  <p>Now I do <code>nuget pack foo.csproj</code>. In the generated .nupkg I get a folder named <code>/lib/portable-net45</code> but I expected something like <code>/lib/portable-net45+dnxcore50</code> so that I can use the package in a DNX project.</p>
  
  <p>Is this intended behavior? How would I go about creating a NuGet package for multiple targets (after all that is what the PCL is for) without manually putting together a folder structure for the NuGet package?</p>
  
  <p>I (the buildserver actually) have built numerous NuGet packages in the way I described above and I expected it to work the same way with PCL projects.</p>