This is more reliable than looking in the environment.
Change-Id: I96c093b89faaece6b6256eefb4a4aac4d66b9cc9
Reviewed-on: https://go-review.googlesource.com/c/146757
Run-TryBot: Michael Matloob <matloob@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Alan Donovan <adonovan@google.com>