diff --git a/include/mbedtls/debug.h b/include/mbedtls/debug.h
index cd522f5..ff8aec0 100644
--- a/include/mbedtls/debug.h
+++ b/include/mbedtls/debug.h
@@ -92,7 +92,7 @@
  *
  * 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)    \