Visual-Studio only _set_printf_count_output

[_set_printf_count_output}(https://docs.microsoft.com/en-us/cpp/c-runtime-library/reference/set-printf-count-output) is a Visual-Studio only function. Therefore, C++ programs that call it should use a preprocessor conditional:

#ifdef _MSC_VER
  _set_printf_count_output();
#endif