[compiler-rt] [ARM][Compiler-RT] Add optional exclusion of libc provided ARM AEABI builtins from compiler-rt. (PR #137952)

[Peter Smith via llvm-commits]

https://github.com/smithp35 approved this pull request.

Thanks for the updates. This looks good to me and should avoid a multiply defined symbol error between picolibc and compiler-rt.

 Please leave some time for other reviewers to comment before merging.

https://github.com/llvm/llvm-project/pull/137952