anchor.diff:      "--disable-debug"
       "--enable-release"
       "--disable-strict"
  -    #"--enable-64bit-libs"
  +    "--enable-shared"
       #"--enable-auto-cleanup"
       "--enable-draft"
       "--enable-renaming"
  
positive.code:     "--disable-weak-threads"
      "--enable-extras"
      "--enable-icuio"
      "--enable-layout"
      #"--enable-layoutex"
      "--enable-tools"
      "--disable-tests"
      "--disable-samples"
      #"--with-library-bits="
    ];
  
    meta = with stdenv.lib; {
      description = "Unicode and globalization support library";
  
negative.code: let
    inherit (stdenv.lib)
      replaceChars;
  
    baseUrls = v: [
      "http://download.icu-project.org/files/icu4c/${v}/icu4c"
    ];
  
    version = "58.1";
  in
  stdenv.mkDerivation rec {
    name = "icu4c-${version}";
  
    src = fetchurl {
      url =
        map (n: "${n}-${replaceChars ["."] ["_"] version}-src.tgz")
            (baseUrls version);
      hashOutput = false;
      sha256 = "0eb46ba3746a9c2092c8ad347a29b1a1b4941144772d13a88667a7b11ea30309";
    };
  
    postUnpack = ''
  