Prepare 6.7.0 3

This should take care of the build issues seen with 6.7.0-2. Sorry it took so long, real life got in the way.

My plan is to upload this to experimental soon, and hopefully import 6.8.0 right afterwards. Assuming everything goes well with 6.7.0-3, I would like to target 6.8.0-1 at unstable rather than experimental.