anchor.diff:  { lib
   , stdenv
   , fetchFromGitHub
  +, fetchpatch
   , makeWrapper
   , pkg-config
   , which
   , bison
   , gnuplot
   , libxls
  +, libxlsxwriter
   , libxml2
   , libzip
   , ncurses
  
positive.code:   buildInputs = [
      gnuplot
      libxls
      libxml2
      libzip
      ncurses
  
negative.code: 
    sourceRoot = "${src.name}/src";
  
    patches = [
      # libxls and libxlsxwriter are not found without the patch
      # https://github.com/andmarti1424/sc-im/pull/542
      (fetchpatch {
        name = "use-pkg-config-for-libxls-and-libxlsxwriter.patch";
        url = "https://github.com/andmarti1424/sc-im/commit/b62dc25eb808e18a8ab7ee7d8eb290e34efeb075.patch";
        sha256 = "1yn32ps74ngzg3rbkqf8dn0g19jv4xhxrfgx9agnywf0x8gbwjh3";
      })
    ];
  
    patchFlags = [ "-p2" ];
  
    nativeBuildInputs = [
      makeWrapper
      pkg-config
  