mapnik2 homebrew formula

mapnik2.rb

require 'formula'

class Mapnik2 < Formula
  head 'http://svn.mapnik.org/trunk/', :using => :svn
  homepage 'http://www.mapnik.org/'

  depends_on 'pkg-config' => :build
  depends_on 'scons' => :build
  depends_on 'libtiff'
  depends_on 'jpeg'
  depends_on 'proj'
  depends_on 'icu4c'
  depends_on 'boost'
  depends_on 'cairomm' => :optional

  def install
    ENV.x11 # for freetype-config

    icu = Formula.factory("icu4c")
    system "scons",
        "PREFIX=#{prefix}",
        "ICU_INCLUDES=#{icu.include}", "ICU_LIBS=#{icu.lib}",
        "JOBS=2", "install"
  end
end

Should line #4 be like:

head 'https://github.com/mapnik/mapnik.git', :using => :git