fix russian chars in xml/rss builder

xml_utf8_fix.rb

class Fixnum #:nodoc:
  XChar = Builder::XChar unless defined?(XChar)

  # XML escaped version of chr (inlines cyrillic unicode range)
  def xchr
    n = XChar::CP1252[self] || self
    n = 42 unless XChar::VALID.find { |value| value.kind_of?(Range) ? value.include?(n) : (value == n) }

    XChar::PREDEFINED[n] or case n
                              when 0...128
                                n.chr
                              when 0x400..0x4FF
                                [n].pack 'U'
                              else
                                "&##{n};"
                            end
  end
end

class String
  # XML escaped version of to_s
  def to_xs
    unpack('U*').map {|n| n.xchr}.join # ASCII, UTF-8
  rescue
    unpack('C*').map {|n| n.xchr}.join # ISO-8859-1, WIN-1252
  end
end