anchor.diff:  
   stdenv.mkDerivation rec {
     pname = "flint";
  -  version = "2.5.2"; # remove libflint.so.MAJOR patch when updating
  +  version = "2.7.1";
     src = fetchurl {
       url = "http://www.flintlib.org/flint-${version}.tar.gz";
  -    sha256 = "11syazv1a8rrnac3wj3hnyhhflpqcmq02q8pqk2m6g2k6h0gxwfb";
  +    sha256 = "07j8r96kdzp19cy3a5yvpjxf90mkd6103yr2n42qmpv7mgcjyvhq";
     };
     buildInputs = [
       gmp
  
positive.code: { lib, stdenv
  , fetchurl
  , fetchpatch
  , gmp
  , mpir
  , mpfr
  
negative.code:   # issues with ntl -- https://github.com/wbhart/flint2/issues/487
    NIX_CXXSTDLIB_COMPILE = "-std=c++11";
  
    doCheck = true;
    meta = {
      inherit version;
  