anchor.diff:  , fetchFromGitLab
   , fetchpatch
   , gmp
  -, python2
  +, python3
   , tune ? false # tune to hardware, impure
   }:
   
   stdenv.mkDerivation rec {
  -  version = "0.9.1";
  +  version = "0.9.2";
     pname = "zn_poly";
   
     # sage has picked up the maintenance (bug fixes and building, not development)
  
positive.code: 
    configureFlags = lib.optionals (!tune) [
      "--disable-tuning"
    ];
  
    patches = [
      # fix format-security by not passing variables directly to printf
      # https://gitlab.com/sagemath/zn_poly/merge_requests/1
      (fetchpatch {
        name = "format-security.patch";
        url = "https://gitlab.com/timokau/zn_poly/commit/1950900a80ec898d342b8bcafa148c8027649766.patch";
        sha256 = "1gks9chvsfpc6sg5h3nqqfia4cgvph7jmj9dw67k7dk7kv9y0rk1";
      })
    ];
  
    # `make install` fails to install some header files and the lib file.
  
negative.code:   ];
  
    nativeBuildInputs = [
      python3 # needed by ./configure to create the makefile
    ];
  
    # name of library file ("libzn_poly.so")
  