altos/samd21: Enable stdio for USB by default

samd21 usb driver didn't bother to enable stdio for USB for some
reason.

Signed-off-by: Keith Packard <keithp@keithp.com>

diff --git a/src/samd21/ao_usb_samd21.c b/src/samd21/ao_usb_samd21.c
index bed4f54adcd59e8a14912b0e510bf48e9536d14f..6b88e8564832b8a4d2ba2b5fca014009ac9148d7 100644 (file)
--- a/src/samd21/ao_usb_samd21.c
+++ b/src/samd21/ao_usb_samd21.c
@@ -28,6 +28,10 @@
 #define AO_USB_DEVICE_ID_SERIAL 0
 #endif
 
+#ifndef USE_USB_STDIO
+#define USE_USB_STDIO  1
+#endif
+
 #if USE_USB_FIFO
 static struct ao_fifo  ao_usb_rx_fifo;
 #endif