[clang] [llvm] [Flang] Search flang_rt in clang_rt path (PR #151954)

[Leandro Lupori via llvm-commits]

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

LGTM, works on my machine.
Thanks for digging deeper into the cause of the problem.

https://github.com/llvm/llvm-project/pull/151954