anchor.diff:      url = "http://double-conversion.googlecode.com/files/double-conversion-${grisu_ver}.tar.gz";
       md5 = "29b533ed4311161267bff1a9a97e2953";
     };
  -  arpack_src = fetchurl rec {
  -    url = "https://github.com/opencollab/arpack-ng/archive/${arpack_ver}.tar.gz";
  -    md5 = "d84e1b6108d9ee67c0d21aba7099e953";
  -    name = "arpack-ng-${arpack_ver}.tar.gz";
  -  };
     utf8proc_src = fetchurl {
       url = "http://www.public-software-group.org/pub/projects/utf8proc/v${utf8proc_ver}/utf8proc-v${utf8proc_ver}.tar.gz";
       md5 = "2462346301fac2994c34f5574d6c3ca7";
  
positive.code: { stdenv, fetchgit, gfortran, perl, m4, llvm, gmp, pcre, zlib
  , readline, fftwSinglePrec, fftw, libunwind, suitesparse, glpk, fetchurl
  , ncurses, libunistring, patchelf, openblas
  , tcl, tk, xproto, libX11, git, mpfr, which
  }:
  
  
negative.code: 
    dsfmt_ver = "2.2";
    grisu_ver = "1.1.1";
    utf8proc_ver = "1.1.6";
  
    dsfmt_src = fetchurl {
  