I can appreciate the pain of actually getting things through in a large (100k+ people) organization.
What do you consider the be the justification for three separate implementations of the same build config language? Genuine question. I am not doubting the need for the DSL itself.
(Note that the Rust implementation is by Facebook, not by Google.)
If you're looking to embed a scripting language in a Go program, having a embedded language implementation written in Java isn't very useful. And vice versa.