anchor.diff: -{ lib, stdenv
  +{ lib
  +, stdenv
   , fetchurl
   , dpkg
   , undmg
  
positive.code:       glib
        gnome2.GConf
        gtk3
        libappindicator-gtk3
        libdrm
        libnotify
  
negative.code:     x86_64-linux = x86_64-linux-version;
    }.${system} or throwSystem;
  
    src =
      let
        base = "https://downloads.slack-edge.com";
      in
        {
          x86_64-darwin = fetchurl {
            url = "${base}/releases/macos/${version}/prod/x64/Slack-${version}-macOS.dmg";
            sha256 = x86_64-darwin-sha256;
          };
          x86_64-linux = fetchurl {
            url = "${base}/linux_releases/slack-desktop-${version}-amd64.deb";
            sha256 = x86_64-linux-sha256;
          };
        }.${system} or throwSystem;
  
    meta = with lib; {
      description = "Desktop client for Slack";
  