7061b27757
add more Cortex-R targets This expands on PR #53663 to complete the set of Cortex-R targets and builds rust-std components for them. r? @alexcrichton each extra rust-std component (there's 4 of them) takes about 3 minutes to build on my local machine. In terms of stability (LLVM codegen bugs) these new targets should be as stable as the Cortex-M ones (e.g. `thumbv7m-none-eabi`). If the extra build time is too much we can leave the rust-std components out for now closes #53663 cc @paoloteti
librustc_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 guide.