Adding Unicode string literals

Hi everyone, I have a question about adding support for foreign languages in my product (touch display). I want to add Chinese/Russian/German and a few other languages. My code workflow is as follows...
Using UNICODE

I want to use UNICODE and get the following error message: .\Output\Lizard.axf: Error: L6218E: Undefined symbol mbsrtowcs (referred from config.o). What do I have to change?
Using UNICODE

I want to use UNICODE and get the following error message: .\Output\Lizard.axf: Error: L6218E: Undefined symbol mbsrtowcs (referred from config.o). What do I have to change?
use of Unicode

How to enable unicode in Uvision 3. Tried to include <tchar.h> but compiler can not find the file. Thanks
use of Unicode

How to enable unicode in Uvision 3. Tried to include <tchar.h> but compiler can not find the file. Thanks