[compiler-rt] [UBSan][Offload] Guard musttail for PowerPC in dlsym interceptor (PR #224273)

[Joseph Huber via llvm-commits]

https://github.com/jhuber6 commented:

I thought I already solved this in https://github.com/llvm/llvm-project/pull/223516? I put it around the entire interceptor interface because `musttail` is required to preserve `RTLD_NEXT` semantics as far as I'm aware. Interceptors shouldn't change the program behavior, ideally.

https://github.com/llvm/llvm-project/pull/224273