anchor.diff:    outputs = [ "out" "doc" ];
   
     patches = [
  -    (fetchpatch { # https://github.com/haskell/haddock/issues/900
  -     url = "https://patch-diff.githubusercontent.com/raw/haskell/haddock/pull/983.diff";
  -     name = "loadpluginsinmodules.diff";
  -     sha256 = "0bvvv0zsfq2581zsir97zfkggc1kkircbbajc2fz3b169ycpbha1";
  -     extraPrefix = "utils/haddock/";
  -     stripLen = 1;
  -   })
     ];
   
     postPatch = "patchShebangs .";
  
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: , # Whetherto build terminfo.
    enableTerminfo ? !stdenv.targetPlatform.isWindows
  
  , 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)
  