[llvm] [OpenMP] Remove usage of pointer-to-member in lookup (PR #123671)

[Michael Kruse via llvm-commits]

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

LGTM.

I could think of some code reorgnization to avoid macro and pointer-to-member arguments (template, or passing a lamba that looks up the requested field), but that doesn't seem worth it for a workaround.

https://github.com/llvm/llvm-project/pull/123671