support cross compile for other arch

[andrewhsu]

Would like to build cli binaries for:

• linux/ppc64le
• linux/s390x

But at the moment gox does not support s390x.

[andrewhsu]

I created PR to add s390x support to gox: mitchellh/gox#85

[dnephin]

FYI #26 might require us to use something other than gox, I'm not sure how that's going to work yet

[tianon]

What's the use case for gox that isn't already solved by simply using GOOS/GOARCH? Go's native cross-compilation support is pretty legendary in my experience (as of around Go 1.5), so I'm curious what gox is adding these days?

[dnephin]

I don't think there is anything special about it. It's just a convenient way to build a bunch of platforms in parallel from a simple command, with templating for the binary name.