The existing implementation generates uncompilable objc code for
functions returning two results.
Change-Id: I13f7329596d8fa6103c4b7827c26c5461e16a925
Reviewed-on: https://go-review.googlesource.com/11364
Reviewed-by: David Crawshaw <crawshaw@golang.org>
Reviewed-by: Hyang-Ah Hana Kim <hyangah@gmail.com>