This makes it easier to integrate this version math into a submodule-ful
world. We'll continue to have regular git tags that parallel the information
in VERSION, so that builds out of this repository behave the same.
Signed-off-by: David Anderson <danderson@tailscale.com>
When building with redo, also include the git commit hash
from the proprietary repo, so that we have a precise commit
that identifies all build info (including Go toolchain version).
Add a top-level build script demonstrating to downstream distros
how to burn the right information into builds.
Adjust `tailscale version` to print commit hashes when available.
Fixes#841.
Signed-off-by: David Anderson <danderson@tailscale.com>
