Currently we use the `go` command to read GOARCH and use the value for
matching manifests.
This change allows:
1. Specifying the arch through `TARGETARCH`
2. Falling back to `dpkg` if `go` is not available
3. Falling back to `uname -m` if `dpkg` is not available
4. A default value (amd64) if none of these commands is available.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
The contrib directory contains scripts, images, and other helpful things
which are not part of the core docker distribution. Please note that they
could be out of date, since they do not receive the same attention as the
rest of the repository.
dedf8528a5