anchor.diff:      brotli
       giflib
       gperftools # provides `libtcmalloc`
  +    libhwy
       libjpeg
       libpng
       libwebp
  
positive.code: , giflib
  , gperftools
  , gtest
  , libjpeg
  , libpng
  , libwebp
  
negative.code:       url = "https://github.com/libjxl/libjxl/commit/88fe3fff3dc70c72405f57c69feffd9823930034.patch";
        sha256 = "1419fyiq4srpj72cynwyvqy8ldi7vn9asvkp5fsbmiqkyhb15jpk";
      })
  
      # "robust statistics" have been removed in upstream mainline as they are
      # conidered to cause "interoperability problems". sure enough the tests
      # fail with precision issues on aarch64.
      (fetchpatch {
        name = "remove-robust-and-descriptive-statistics.patch";
        url = "https://github.com/libjxl/libjxl/commit/204f87a5e4d684544b13900109abf040dc0b402b.patch";
        sha256 = "sha256-DoAaYWLmQ+R9GZbHMTYGe0gBL9ZesgtB+2WhmbARna8=";
      })
    ];
  
    nativeBuildInputs = [
      asciidoc # for docs
  