This replaces the DisableFlagsInUseLine call from the CLI with a test
that verifies the option is set for all commands and subcommands, so
that it doesn't have to be modified at runtime.
Signed-off-by: Sebastiaan van Stijn <github@gone.nl>
This allows the buildx CLI to act a proxy to the configured instance.
It allows external code to use buildx itself as a driver for connecting
to buildkitd instances.
Instance and node selection should follow the same semantics as as
`buildx build`, including taking into account the `BUILDX_BUILDER` env
var and the `--builder` global flag.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>