If anything, that check should be for OS X.

But I still find this rather suspicious, that `__cplusplus` is always 201103. I checked on a nearby Mac, which has OS X 10.7, whose clang is also based on 3.2, and there's no such thing there. I haven't been able to find any mention of this online, either. Did you test it via something simple like `echo __cplusplus | clang++ -xc++ -E -`?