Correct include guard for function __attribute
*
* This module provides debugging functions.
*/
-#if (defined(_WIN32) || defined(_WIN64))
+#if defined(__GNUC__)
#define MBEDTLS_PRINTF_ATTRIBUTE(string_index, first_to_check)
#else
#define MBEDTLS_PRINTF_ATTRIBUTE(string_index, first_to_check) \
