By the time Go 1.11 is released, OS X 10.9 Mavericks will have gone
two years with no security updates.

For #23011.

Change-Id: I6482852a14477985769b72c45c92416aae8be100
Reviewed-on: https://go-review.googlesource.com/83795
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>