anchor.diff:  , # Whetherto build terminfo.
     enableTerminfo ? !stdenv.targetPlatform.isWindows
   
  -, version ? "8.9.20190924"
  +, version ? "8.10.20191119"
   , # What flavour to build. An empty string indicates no
     # specific flavour and falls back to ghc default values.
     ghcFlavour ? stdenv.lib.optionalString (stdenv.targetPlatform != stdenv.hostPlatform)
  
positive.code: 
    src = fetchgit {
      url = "https://gitlab.haskell.org/ghc/ghc.git/";
      rev = "795986aaf33e2ffc233836b86a92a77366c91db2";
      sha256 = "0a111x6c53r07q5qdg6c8mnydqp0wh4mpxmw7ga4x5wlap8i0bji";
    };
  
    enableParallelBuilding = true;
  
negative.code:   # Splicer will pull out correct variations
    libDeps = platform: stdenv.lib.optional enableTerminfo [ ncurses ]
      ++ stdenv.lib.optional (!enableIntegerSimple) gmp
      ++ stdenv.lib.optional (platform.libc != "glibc" && !targetPlatform.isWindows) libiconv
      ++ stdenv.lib.optional enableDwarf elfutils;
  
    toolsForTarget = [
      pkgsBuildTarget.targetPackages.stdenv.cc
  