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: 
  # build-tools
  , bootPkgs
  , autoconf, automake, coreutils, fetchgit, fetchpatch, perl, python3, m4, sphinx
  , bash
  
  , libiconv ? null, ncurses
  
  , useLLVM ? !stdenv.targetPlatform.isx86
  , # LLVM is conceptually a run-time-only depedendency, but for
  
negative.code: 
    src = fetchgit {
      url = "https://gitlab.haskell.org/ghc/ghc.git/";
      rev = "0418c38d55c7a47967187dce2db5ea2ab1021b1e";
      sha256 = "1d8g30ii0w4xh6fh61bxbalsqqyanny99nn3p727fx7favnhgvxi";
    };
  
    enableParallelBuilding = true;
  