Go on NetBSD needs love

Hi,

I work on Go (https://golang.org) and run our build farm (
https://build.golang.org/).

Go's main toolchain supports 38 different OS/arch pairs (`go tool dist
list`), not including gccgo.

Three of those 38 are:

netbsd/386
netbsd/amd64
netbsd/arm

And those three are currently in need of love.

We've had problems with both hangs during builds as well as kernel crashes,
so we've had to stop running our NetBSD builders during the last dev cycle,
as sadly added to our upcoming Go 1.9 release notes:

    https://tip.golang.org/doc/go1.9#known_issues

If any NetBSD developers have time and/or interest, these bugs need
attention:

    https://github.com/golang/go/labels/OS-NetBSD

Most concerning is our builders kernel panicing:

    https://github.com/golang/go/issues/20836

Until that's fixed, it's hard to make forward progress on other issues.

Thanks!
Brad