Nix overlay for Wine 4

wine_4.nix

# I thought this might allow running Adobe Digital Editions 2.0.1 but it didn't work.
# Leaving a gist so that I don't need to look up the commit when I need it again.
self: super:
let
  pkgsPath = builtins.fetchTarball {
    url = "https://github.com/NixOS/nixpkgs/archive/8a83fb70d01a953ef72293e0034474a5a93ef3c0.tar.gz";
    sha256 = "0f2blhwpy5vbxzrbyykn0jk0da9srgnfv4yaxi3yhmlpinlx84m9";
  };
in {
  wine_4 = (import pkgsPath { }).wineUnstable;
}