anchor.diff:  { stdenv, fetchgit, gfortran, perl, m4, llvm, gmp, pcre, zlib
   , readline, fftwSinglePrec, fftw, libunwind, suitesparse, glpk, fetchurl
  -, ncurses, libunistring, patchelf, openblas, arpack
  -, tcl, tk, xproto, libX11, git, mpfr, which
  +, ncurses, patchelf, openblas, arpack
  +, tcl, tk, xproto, libX11, git, mpfr, which, utf8proc
   }:
   
   with stdenv.lib;
  
positive.code:     "-lopenblas"
      "-lpcre"
      "-lsuitesparse"
      "-lunistring"
      "-lz"
    ];
  
  
negative.code:       "LIBLAPACKNAME=libopenblas"
  
        "USE_SYSTEM_ARPACK=1"
  
        "USE_SYSTEM_UTF8PROC=1"
      ];
  
    GLPK_PREFIX = "${glpk}/include";
  