Create * .mdb file with Visual Studio 2017 for PCL

I want to create a NuGet package from PCL that defines .NET, UWP, Android (Xamarin), iOS (Xamarin), etc. (for example, Profile111 example).

When I reference a project in an Android application, Visual Studio 2017 creates a * .mdb file that uses the mono debugger to enable cross-cutting code.

Now I am not getting the same result with a solution / project that just contains the PCL code.

What I got when I compiled my sample.csproj with VS2017,

sample.dll
sample.pdb

      

        
        
        
      

    

what is missing:

sample.dll.mdb 

      

        
        
        
      

    

In the end, I want to create a nuspec file like this: https://github.com/xamarin/Xamarin.Forms/pull/167/files

Every hint is appreciated.

Tank Alex