anchor.diff:  
   let
     pname = "wlroots";
  -  version = "0.2";
  +  version = "0.3";
   in stdenv.mkDerivation rec {
     name = "${pname}-${version}";
   
  
positive.code:     owner = "swaywm";
      repo = "wlroots";
      rev = version;
      sha256 = "0gfxawjlb736xl90zfv3n6zzf5n1cacgzflqi1zq1wn7wd3j6ppv";
    };
  
    postPatch = ''
      substituteInPlace meson.build \
        --replace "version: '0.1.0'" "version: '${version}.0'"
    '';
  
    # $out for the library, $bin for rootston, and $examples for the example
    # programs (in examples) AND rootston
  
negative.code:     "-Dlibcap=enabled" "-Dlogind=enabled" "-Dxwayland=enabled" "-Dx11-backend=enabled"
      "-Dxcb-icccm=enabled" "-Dxcb-errors=enabled"
    ];
  
    postPatch = ''
      # It happens from time to time that the version wasn't updated:
      sed -iE "s/version: '[0-9]\.[0-9]\.[0-9]'/version: '${version}.0'/" meson.build
    '';
  
    postInstall = ''
      # Install rootston (the reference compositor) to $bin and $examples
  