I confirm this bug has not already been reported

• I have searched the issues and this bug has not been reported previously

Describe the bug
Using flake.nix is broken, for official unstable nixpkgs. This is currently not an issue if user is using flake.nix without overriding to their local (latest unstable) nixpkgs. But eventually this will be an issue also here - when someone updates flake.lock inputs with latest one.

To Reproduce
Steps to reproduce the behaviour:

1. Use flake.nix in your own flake:

{
  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
    quickemu = {
      url = "github:quickemu-project/quickemu";
      inputs.nixpkgs.follows = "nixpkgs";  # using your own unstable nixpkgs
    };
  };
}

2. See error:

error: 'glxinfo' has been renamed to/replaced by 'mesa-demos'

Expected behaviour
To not get the error.

Additional info
The fix is just to rename the offending package (and to update nixpkgs in flake.lock):

• here https://github.com/quickemu-project/quickemu/blob/master/package.nix#L10
• and here https://github.com/quickemu-project/quickemu/blob/master/package.nix#L54

But since I believe glxinfo executable is just a test program which is usually used only for checking how many FPS do you get... So is this even required, could we get rid of this dependency?