decker: remove package

It's been upstreamed to nixpkgs.

pkgs/decker/default.nix

@@ -1,60 +0,0 @@
-{ stdenv
-, lib
-, fetchFromGitHub
-, SDL2
-, SDL2_image
-, unixtools
-, multimarkdown
-}:
-
-stdenv.mkDerivation rec {
-  pname = "decker";
-  version = "1.7";
-
-  src = fetchFromGitHub {
-    owner = "JohnEarnest";
-    repo = "Decker";
-    rev = "v${version}";
-    sha256 = "sha256-yfUD+qvINx0QLvXwuc4MTEK/Z1tcHpy0ZK4peCfkozk=";
-  };
-
-  buildInputs = [
-    SDL2
-    SDL2_image
-    multimarkdown
-    unixtools.xxd
-  ];
-
-  buildPhase = ''
-    make lilt
-    make decker
-    make docs
-  '';
-
-  installPhase = ''
-    runHook preInstall
-
-    install -Dm0755 ./c/build/lilt -t $out/bin
-    install -Dm0755 ./c/build/decker -t $out/bin
-    install -Dm0644 ./syntax/vim/ftdetect/lil.vim -t $out/etc/xdg/vim/ftdetect
-    install -Dm0644 ./syntax/vim/syntax/lil.vim -t $out/etc/xdg/vim/syntax
-    install -Dm0644 ./examples/decks/*.deck -t $out/share/decker/examples/decks
-    install -Dm0644 ./examples/lilt/*.lil -t $out/share/decker/examples/lilt
-
-    mkdir -p $out/share/doc
-    cp -r ./docs/* $out/share/doc
-
-    runHook postInstall
-  '';
-
-  postPatch = ''
-    patchShebangs ./scripts/*
-  '';
-
-  meta = with lib; {
-    homepage = "https://beyondloom.com/decker";
-    description = "Multimedia platform for creating and sharing interactive documents";
-    license = licenses.mit;
-    platforms = platforms.all;
-  };
-}

pkgs/default.nix

@@ -11,7 +11,6 @@ let
       aw-watcher-window-wayland = callPackage ./aw-watcher-window-wayland { };
       blender-blendergis = python3Packages.callPackage ./blender-blendergis { };
       blender-machin3tools = python3Packages.callPackage ./blender-machin3tools { };
-      decker = callPackage ./decker { };
       cosmic-launcher = callPackage ./cosmic-launcher { };
       clidle = callPackage ./clidle.nix { };
       domterm = libsForQt5.callPackage ./domterm { };