Same was done in CL 7940 for the syscall package.

Fixes golang/go#10838

Change-Id: I98efa99f57f21bdcdbfb117af66f673e37767fec
Reviewed-on: https://go-review.googlesource.com/103335
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>