anchor.diff:    };
   
     nativeBuildInputs = [ cmake ];
  -  buildInputs = [ llvmMerged ncurses libxml2 ];
  +  buildInputs = [ llvmMerged ncurses libxml2 ] ++ lib.optional enableCUDA cuda;
   
     cmakeFlags = [
       "-DHAS_TERRA_VERSION=0"
       "-DTERRA_VERSION=${src.rev}"
       "-DTERRA_LUA=luajit"
  -  ];
  +  ] ++ lib.optional enableCUDA "-DTERRA_ENABLE_CUDA=ON";
   
     doCheck = true;
     enableParallelBuilding = true;
  
positive.code: { lib, stdenv, fetchurl, fetchFromGitHub, llvmPackages, ncurses, cmake, libxml2
  , symlinkJoin, breakpointHook }:
  
  let
    luajitRev = "9143e86498436892cb4316550be4d45b68a61224";
  
negative.code:       clang-unwrapped.lib
      ];
    };
    cuda = cudaPackages.cudatoolkit_11;
  in stdenv.mkDerivation rec {
    pname = "terra";
    version = "1.0.0-beta3";
  