Merge "Explain why there are two licenses in here." am: 7ea5aa9624 am: 7809db48d8 am: 2999cd7058 am: 0ba865af92

Original change: https://android-review.googlesource.com/c/platform/external/zopfli/+/1736675

Change-Id: I76dfce1eb923cc3f0397ee8046cf2e7751a5baac