b20e3ff2af
Refactor linker code This merges `LinkerInfo` into `CrateInfo` as there is no reason to keep them separate. `LinkerInfo::to_linker` is merged into `get_linker` as both have different logic for each linker type and `to_linker` is directly called after `get_linker`. Also contains a couple of small cleanups. See the individual commits for all changes.
Please read the rustc-dev-guide chapter on Backend Agnostic Codegen.