There's nothing specific to mac in the PublicSuffix unit tests. In r186023, I moved the test to WebCore/PublicSuffix.cpp and fixed it, because PublicSuffix.mm has #if USE(PUBLIC_SUFFIX_LIST) instead of #if ENABLE(). I couldn't do that change as part of r186023 because it requires to change xcode files, so it's should be easy for someone with a mac.