code: private String getCharacterSet(final CommandLineCompilerConfiguration compilerConfig) {
      final String[] args = compilerConfig.getPreArguments();
      String charset = "0";
      for (final String arg : args) {
        if ("/D_UNICODE".equals(arg) || "/DUNICODE".equals(arg)) {
          charset = "1";
        }
        if ("/D_MBCS".equals(arg)) {
          charset = "2";
        }
      }
      return charset;
    }
docs: Get character set for Windows API.
  
  @param compilerConfig
  compiler configuration, may not be null.
  @return "1" is TCHAR is unicode, "0" if TCHAR is multi-byte.