Some character disappear on mac os x

std::isspace() of mac os x recognize 0xa0 as whitespace.
I think that it's a bug.
http://en.cppreference.com/w/cpp/string/byte/isspace

'죠' is 0xec, 0xa3, 0xa0
'고' 0xea, 0xb3, 0xa0
Both '죠' and '고' have 0xa0.

Perhaps more character will be affected.