anchor.diff:  
   stdenv.mkDerivation rec {
     name = "aseprite-${version}";
  -  version = if unfree then "1.2.4" else "1.1.7";
  +  version = if unfree then "1.2.9" else "1.1.7";
   
     src = fetchFromGitHub {
       owner = "aseprite";
  
positive.code:     "-DWITH_WEBP_SUPPORT=ON"
    ] ++ lib.optionals unfree [
      "-DUSE_SHARED_CMARK=ON"
      # Aseprite needs internal freetype headers.
      "-DUSE_SHARED_FREETYPE=OFF"
      # Disable libarchive programs.
  
negative.code: { stdenv, lib, fetchFromGitHub, fetchpatch, cmake, pkgconfig
  , curl, freetype, giflib, harfbuzz, libjpeg, libpng, libwebp, pixman, tinyxml, zlib
  , libX11, libXext, libXcursor, libXxf86vm
  , unfree ? false
  , cmark
  