builder: support cross variant copying for builder.requirements
Allow builder.requirements to use a long form similar to copies when
the user needs to copy files from one variant to another as part of the
builder stage. This allows multi-stage builds to generate some artifact
in stage "A" and then copy that artifact into stage "B" in the
PreInstall phase before running builder.command.
variants: A: apt: packages: - wget builder: command: - /bin/bash - -c - >- wget https://example.org/some_cool_utility.tgz && tar xzvf some_cool_utility.tgz && rm some_cool_utility.tgz B: builder: requirements: - src - from: A source: some_cool_utility destination: . command: - some_cool_utility --do-something-cool src/
Co-authored-by: Dan Duvall <email@example.com>