Triggers 21 times during make.bash.

Change-Id: I7efb34200439256151304bb66cd309913f7c9c9e
Reviewed-on: https://go-review.googlesource.com/110557
Run-TryBot: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Martin Möhrmann <moehrmann@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>