Brad Fitzpatrick showed up on the users@ list and mentioned that for DragonFly to be supported in Go, it needed to show up in the Go Dashboard with building reports. I now have the Go builder running on pkgbox32/pkgbox64.dragonflybsd.org. Check the builder page to see status.
Note: Installing the port of Go from Dports works just fine; this is the mechanism for testing Go on a per-commit basis for the people who work on Go – so a ‘fail’ notice on the builder page doesn’t necessarily mean anything, unless you are developing Go itself. This may already be clear to you.