I'm trying to implement Facebook login with the Facebook SDK for Unity. The documentation makes it sound pretty straightforward: call FB.Init and then call FB.LogInWithReadPermissions and use a callback to handle the response. At no point does it mention any additional requirements, such as specific gaming clients.
Everything works inside the editor, but when I try to run a build, the Init call fails with the error message "Pipe name not passed to application on start. Make sure you are running inside the facebook games client."
...yeah. That's kind of what I'm trying to specifically not do here; this is being built to run on Steam, and I have seen other Steam games offer Facebook authentication, so I know it's possible. I just don't quite know how, and Facebook's documentation is no help because it doesn't even mention Gameroom in conjunction with these APIs at all!
Does anyone know what the proper way is to set this up? Using Unity 2019.2.2f1 and Facebook SDK 7.17.2.