lib/utils/printf: Consistently #undef functions defined in this file.
Triggered by Newlib from Zephyr SDK 0.10.0 which #define's those if SSP
stack protector is enabled (which is default), leading to compile error.
@@ -49,7 +49,13 @@ int DEBUG_printf(const char *fmt, ...) {
#if MICROPY_USE_INTERNAL_PRINTF
-#undef putchar // Some stdlibs have a #define for putchar
+// Some stdlibs have #define's for various stdio funcs
+#undef printf
+#undef vprintf
+#undef putchar
+#undef puts
+#undef vsnprintf
+#undef snprintf
int printf(const char *fmt, ...);
int vprintf(const char *fmt, va_list ap);
int putchar(int c);
