Add File as Link (in Visual Stuido 2019)

Question

I saw a post that described adding source files to a project as a link. This would be ideal for something I wanted to do, where the file was generated by another program.

Unfortunately, in my version of Developer Studio the option has been removed (or perhaps moved to some other place).

I'm running "Microsoft Visual Studio Community 2019 Preview". Is this option no longer supported, or is it only supported in some other version.

In case it matters I was trying to add this file to a C++ Native Test project.