anchor.diff:          + head (splitString "." version)
           + ".x/${version}/mesa-${version}.tar.xz")
       ];
  -    multihash = "Qmci7BC3LTxiLVjdZyV8KsUftcp8ocoXRs7AK2K5vXC795";
  +    multihash = "QmTZJ4bQcVnHMqGs6Q8jqwB4ZbasYWRfo7oa3CHKfnAew6";
       hashOutput = false;  # Provided by upstream directly
  -    sha256 = "39db3d59700159add7f977307d12a7dfe016363e760ad82280ac4168ea668481";
  +    sha256 = "96fd70ef5f31d276a17e424e7e1bb79447ccbbe822b56844213ef932e7ad1b0c";
     };
   
     nativeBuildInputs = [
  
positive.code:     optionalString
      splitString;
  
    version = "17.0.0";
  
    # this is the default search path for DRI drivers
    driverSearchPath = "/run/opengl-driver-${stdenv.targetSystem}";
  
negative.code: 
    src =  fetchurl {
      urls = [
        "https://mesa.freedesktop.org/archive/mesa-${version}.tar.xz"
        "https://mesa.freedesktop.org/archive/${version}/mesa-${version}.tar.xz"
        "ftp://ftp.freedesktop.org/pub/mesa/${version}/mesa-${version}.tar.xz"
        # Tarballs for old releases are moved to another directory
  