To be used e.g. in
https://github.com/gokrazy/gokrazy/commit/2e60d5b8c8c35e0eed1bb155c7d709c729c8f041

Change-Id: If79ffec9021dc79375c861a0ddd9dd443adb4692
Reviewed-on: https://go-review.googlesource.com/72375Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>