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

[via llvm-commits]

Andarwinux wrote:

In order to fix LTO+llvm-libc, is it only the ELF backend of LLD that needs special handling? Or only ELF is considered as a prototype for now? I experimented with LTO+overlay llvm-libc+-fbuiltin on Windows/COFF and everything seems to work fine, even without these changes.

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