Current versions of gccgo report a redefinition error for both a
declaration and definition, as of https://golang.org/cl/93083.
Fix the last change to work with this.

Change-Id: Iae6a664fcc9fe97d4e3b7845a05dab3a8ad56830
Reviewed-on: https://go-review.googlesource.com/116776
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>