anchor.diff:    # https://downloads.haskell.org/~ghc/8.6.5/
     src = fetchurl ({
       i686-linux = {
  +      # Don't use the Fedora27 build (as below) because there isn't one!
         url = "http://haskell.org/ghc/dist/${version}/ghc-${version}-i386-deb9-linux.tar.xz";
         sha256 = "1p2h29qghql19ajk755xa0yxkn85slbds8m9n5196ris743vkp8w";
       };
       x86_64-linux = {
  -      url = "http://haskell.org/ghc/dist/${version}/ghc-${version}-x86_64-deb9-linux.tar.xz";
  -      sha256 = "1pqlx6rdjs2110g0y1i9f8x18lmdizibjqd15f5xahcz39hgaxdw";
  +      # This is the Fedora build because it links against ncurses6 where the
  +      # deb9 one links against ncurses5, see here
  +      # https://github.com/NixOS/nixpkgs/issues/85924 for a discussion
  +      url = "http://haskell.org/ghc/dist/${version}/ghc-${version}-x86_64-fedora27-linux.tar.xz";
  +      sha256 = "18dlqm5d028fqh6ghzn7pgjspr5smw030jjzl3kq6q1kmwzbay6g";
       };
       aarch64-linux = {
         url = "http://haskell.org/ghc/dist/${version}/ghc-${version}-aarch64-ubuntu18.04-linux.tar.xz";
  
positive.code:     '' +
      # Rename needed libraries and binaries, fix interpreter
      stdenv.lib.optionalString stdenv.isLinux ''
        find . -type f -perm -0100 -exec patchelf \
            --replace-needed libncurses${stdenv.lib.optionalString stdenv.is64bit "w"}.so.5 libncurses.so \
            --replace-needed libtinfo.so libtinfo.so.5 \
            --interpreter ${glibcDynLinker} {} \;
  
        sed -i "s|/usr/bin/perl|perl\x00        |" ghc-${version}/ghc/stage2/build/tmp/ghc-stage2
  
negative.code: { stdenv
  , fetchurl, perl, gcc
  , ncurses5, ncurses6, gmp, glibc, libiconv
  , llvmPackages
  }:
  
  