ChibiOS 2.6.8, until I can figure out where to get it from git.

firmware/chibios/demos/AVR-ArduinoMega-GCC/mcuconf.h

@@ -0,0 +1,49 @@
+/*
+    ChibiOS/RT - Copyright (C) 2006-2013 Giovanni Di Sirio
+
+    Licensed under the Apache License, Version 2.0 (the "License");
+    you may not use this file except in compliance with the License.
+    You may obtain a copy of the License at
+
+        http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing, software
+    distributed under the License is distributed on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+    See the License for the specific language governing permissions and
+    limitations under the License.
+*/
+
+/*
+ * AVR drivers configuration.
+ * The following settings override the default settings present in
+ * the various device driver implementation headers.
+ * Note that the settings for each driver only have effect if the driver
+ * is enabled in halconf.h.
+ */
+
+/*
+ * ADC driver system settings.
+ */
+
+/*
+ * CAN driver system settings.
+ */
+
+/*
+ * MAC driver system settings.
+ */
+
+/*
+ * PWM driver system settings.
+ */
+
+/*
+ * SERIAL driver system settings.
+ */
+#define USE_AVR_USART0              TRUE
+#define USE_AVR_USART1              FALSE
+
+/*
+ * SPI driver system settings.
+ */