C++ Unresolved External: CkString::appendU

In VC++ 7.0, 8.0, 9.0, and 10.0, make sure the C++ Language option ‘Treat WChar_t as Built In Type’ is set to Yes. Otherwise, you may get this link error:

error LNK2019: unresolved external symbol "public: void __cdecl CkString::appendU(unsigned short const *)