they don't support C99 varargs macros.
#if defined(CURL_DISABLE_VERBOSE_STRINGS)
#if defined(__GNUC__)
-/* Variable argument macros is a C99 feature long supported by gcc */
-#define infof(...) /*ignore*/
+/* This style of variable argument macros is a gcc extension */
+#define infof(x...) /*ignore*/
#else
+/* C99 compilers could use this if we could detect them */
+/*#define infof(...) */
/* Cast the args to void to make them a noop, side effects notwithstanding */
#define infof (void)
#endif