Analogous to https://go-review.googlesource.com/#/c/8457/ this
code synthesizes an set of program arguments for Android on the
arm64 architecture.

Change-Id: I851958b4b0944ec79d7a1426a3bb2cfc31746797
Reviewed-on: https://go-review.googlesource.com/17782Reviewed-by: David Crawshaw <crawshaw@golang.org>
Run-TryBot: David Crawshaw <crawshaw@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>