adding flag/task for building with es5 packages
adding flag/task for building with es5 packages


Former-commit-id: 73d1aca1640d527d1c32609362c8fb0100850651 [formerly 702b4732740f12af9c942060a2856c93f14c1477]
Former-commit-id: 8dc1675f19a9f4671df344f4896829a6fc3a29ce
andrewplummer/Sugar,romancow/Sugar,andrewplummer/Sugar,romancow/Sugar