def generate_builtin_set(system_plugins=[])
      builtin_set = BuiltinSet.new
      @logger.debug("Generating new builtin set instance.")
      vagrant_internal_specs.each do |spec|
        if !system_plugins.include?(spec.name)
          builtin_set.add_builtin_spec(spec)
        end
      end
      builtin_set
    end
def generate_builtin_set(system_plugins=[])
      builtin_set = BuiltinSet.new
      @logger.debug("Generating new builtin set instance.")
      vagrant_internal_specs.each do |spec|
        if !system_plugins.include?(spec.name)
          builtin_set.add_builtin_spec(spec)
        end
      end
      builtin_set
    end
Generate the builtin resolver set