go fmt
The new `go fmt` adds `//go:build` lines (https://golang.org/doc/go1.17#tools). Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>
This allows using the utility without bringing whole of "sys" with it. Signed-off-by: Sebastiaan van Stijn <github@gone.nl>