[clang] [lld] [llvm] [LTO][LLD] Prevent invalid LTO libfunc transforms (PR #164916)

[Daniel Thornburgh via cfe-commits]

mysterymath wrote:

Alright, AFAICT, that last push should address all the outstanding comments. Is there anything else to do on this PR?

https://github.com/llvm/llvm-project/pull/164916