[dev.power64] runtime: fix build
[dev.power64] runtime: fix build

LGTM=rsc
R=rsc, iant
CC=golang-codereviews
https://codereview.appspot.com/128180044

Committer: Russ Cox <5ad239cb8a44f659eaaee0aa1ea5b94947abe557@golang.org>

bryanxu/go-zh,bryanxu/go-zh,d0f/go-zh,bryanxu/go-zh,d0f/go-zh,webfd/go-zh,d0f/go-zh,webfd/go-zh,bryanxu/go-zh,d0f/go-zh,bryanxu/go-zh,webfd/go-zh,webfd/go-zh,webfd/go-zh,d0f/go-zh,webfd/go-zh,bryanxu/go-zh,webfd/go-zh,bryanxu/go-zh,d0f/go-zh,d0f/go-zh,webfd/go-zh,bryanxu/go-zh,d0f/go-zh