itself non-throwing. Since nested_exception's destructor is
non-throwing, if B's destructor is not, this causes an error in C++03
mode due to the overriding function having a more lax specification.
This did not occur in C++0x mode as A's destructor was implicitly
non-throwing.
git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@135400 91177308-0d34-0410-b5e6-96231b3b80d8
