Refactor Apple `target_abi` This was bundled together with `Arch`, which complicated a few code paths and meant we had to do more string matching than necessary. CC `@BlackHoleFox` as you've worked on the Apple target spec before Related: Is there a reason why `Target`/`TargetOptions` use `StaticCow` for so many things, instead of an enum with defined values (and perhaps a catch-all case for custom target json files)? Tagging `@Nilstrieb,` as you might know?
rustc_target
contains some very low-level details that are
specific to different compilation targets and so forth.
For more information about how rustc works, see the rustc dev guide.