runtime: fix windows build
runtime: fix windows build

#ifdef'ed out code wasn't updated for argp change.

TBR=iant
CC=golang-codereviews
https://codereview.appspot.com/139040043

d0f/go-zh,sanjosh/sanjos100-tipc,bryanxu/go-zh,webfd/go-zh,bryanxu/go-zh,bryanxu/go-zh,sanjosh/sanjos100-tipc,d0f/go-zh,sanjosh/sanjos100-tipc,webfd/go-zh,d0f/go-zh,sanjosh/sanjos100-tipc,webfd/go-zh,sanjosh/sanjos100-tipc,d0f/go-zh,sanjosh/sanjos100-tipc,webfd/go-zh,bryanxu/go-zh,d0f/go-zh,webfd/go-zh,d0f/go-zh,bryanxu/go-zh,webfd/go-zh,bryanxu/go-zh,bryanxu/go-zh,sanjosh/sanjos100-tipc,webfd/go-zh,webfd/go-zh,d0f/go-zh,sanjosh/sanjos100-tipc,d0f/go-zh,bryanxu/go-zh