No need to type this global as an unsafe.Pointer, we know
what type the referent is.

Change-Id: I7b1374065b53ccf1373754a21d54adbedf1fd587
Reviewed-on: https://go-review.googlesource.com/67990Reviewed-by: Daniel Martí <mvdan@mvdan.cc>
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>