bpo-45405: Prevent ``internal configure error`` when running ``configure`` ...

bpo-45405: Prevent ``internal configure error`` when running ``configure``  with recent versions of non-Apple clang. (#28845)

Change the configure logic to function properly on macOS when the compiler
outputs a platform triplet for option --print-multiarch.

Co-authored-by: Ned Deily <nad@python.org>