feat(tvix/eval): support `Derivation` context elements r/7805

Derivation that depends on `${d.drvPath}` generates a `NixContextElement::Derivation(drvPath)` context string.
In turn, this makes the dependent derivation depend on *ALL* outputs of that derivation.

Note that a dependency on `${d.drvPath}` generates an input source
dependency too.

This is a complete implementation of the context string system in Nix on
the "input population" side.

The test coverage of this change is taken care in cl/11264.

Change-Id: I97fe5f7c772a6b1cc4366bee071aa691a11fcde6
Signed-off-by: Ryan Lahfa <tvl@lahfa.xyz>
Reviewed-on: https://cl.tvl.fyi/c/depot/+/11261
Reviewed-by: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI

0 files changed, 0 insertions, 0 deletions