[clang] [llvm] [LinkerWrapper] Always pass `-flto` if the linker supports it (PR #102972)

[Joseph Huber via cfe-commits]

jhuber6 wrote:

> This caused a nvlink error with clang. This was found by a OpenMP CI https://gitlab.e4s.io/uo-public/llvm-openmp-offloading/-/jobs/301520

Probably an LTO flag I forgot to handle correctly, can you compile it with `-v` to show what it's passing?

https://github.com/llvm/llvm-project/pull/102972