anchor.diff:  # (to make gems behave if necessary).
   
   { lib, fetchurl, writeScript, ruby, libxml2, libxslt, python, stdenv, which
  -, postgresql, v8_3_16_14, clang }:
  +, libiconv, postgresql, v8_3_16_14, clang }:
   
   let
     v8 = v8_3_16_14;
  
positive.code: 
  {
    bundler = attrs: {
      dontPatchShebangs = 1;
    };
  
    libv8 = attrs: {
  
negative.code: 
    nokogiri = attrs: {
      buildFlags = [
        "--use-system-libraries"
        "--with-zlib-dir=${zlib}"
        "--with-xml2-lib=${libxml2}/lib"
        "--with-xml2-include=${libxml2}/include/libxml2"
        "--with-xslt-lib=${libxslt}/lib"
        "--with-xslt-include=${libxslt}/include"
        "--with-exslt-lib=${libxslt}/lib"
        "--with-exslt-include=${libxslt}/include"
        "--with-iconv-dir=${libiconv}"
      ];
    };
  
    pg = attrs: {
      buildFlags = [
        "--with-pg-config=${postgresql}/bin/pg_config"
      ];
    };
  
    rmagick = attrs: {
      buildInputs = [ imagemagick pkgconfig ];
    };
  
    sqlite3 = attrs: {
      buildFlags = [
        "--with-sqlite3-include=${sqlite}/include"
        "--with-sqlite3-lib=${sqlite}/lib"
      ];
    };
  
  