Requested feature: We should be able to configure the compiler without having to modify its code.
Use case: Provide a robust and clean compilation module for RMC.
Link to relevant documentation (Rust reference, Nomicon, RFC):
Is this a breaking change? No

Success criteria: We replace rmc-rustc by a rust application call. I.e., this issue only covers the creation of the RMC compiler driver on the top of rustc. Follow up issues will track moving more logic out of our python scripts into an RMC application.