anchor.diff:  let
     # Release calendar: https://www.mesa3d.org/release-calendar.html
     # Release frequency: https://www.mesa3d.org/releasing.html#schedule
  -  version = "21.1.7";
  +  version = "21.2.1";
     branch  = versions.major version;
   
   self = stdenv.mkDerivation {
  
positive.code:       "ftp://ftp.freedesktop.org/pub/mesa/${version}/mesa-${version}.tar.xz"
        "ftp://ftp.freedesktop.org/pub/mesa/older-versions/${branch}.x/${version}/mesa-${version}.tar.xz"
      ];
      sha256 = "1fx7nfvh1drfa6vv34j7ma944qbs014b0jwlbgqlnbjgcl87rrp9";
    };
  
    prePatch = "patchShebangs .";
  
    # TODO:
    #  revive ./dricore-gallium.patch when it gets ported (from Ubuntu), as it saved
  
negative.code:   ];
  
    postPatch = ''
      patchShebangs .
  
      substituteInPlace meson.build --replace \
        "find_program('pkg-config')" \
        "find_program('${buildPackages.pkg-config.targetPrefix}pkg-config')"
  