* fix: support empty CIBW_PLATFORM Signed-off-by: Henry Schreiner <henryschreineriii@gmail.com> * fix: support empty CIBW_PLATFORM * Add test --------- Signed-off-by: Henry Schreiner <henryschreineriii@gmail.com> Co-authored-by: mayeut <mayeut@users.noreply.github.com>