# File lib/dep_selector/dependency_graph.rb, line 52
    def generate_gecode_wrapper_constraints(packages_to_include_in_solve=nil)
      unless @gecode_wrapper
        packages_in_solve =
          if packages_to_include_in_solve
            packages_to_include_in_solve
          else
            packages.map{ |name, pkg| pkg }
          end

        # In addition to all the packages that the user specified,
        # there is a "ghost" package that contains the solution
        # constraints. See Selector#solve for more information.
        @gecode_wrapper = GecodeWrapper.new(packages_in_solve.size + 1)
        packages_in_solve.each{ |pkg| pkg.generate_gecode_wrapper_constraints }
      end
    end