The keyboard works fine though, I tried it. I built the latest commit and I'm using an Xbox 360 controller.
As soon as I plug in my PS4-controller and try to assign a button, I will get the 'keyboard: ?' How to get a Nintendo 64 Controller to work with Project 64? I have it running right now. Our N64 to USB adapter works very well with this emulator. Make sure you check the box that tells P64 that your controller is plugged in.