add RT_USING_CONSOLE option.

git-svn-id: https://rt-thread.googlecode.com/svn/trunk@1535 bbd45198-f89e-11dd-88c7-29a3b14d5316

bsp/lpc176x/rtconfig.h

@@ -64,6 +64,7 @@
 #define RT_UART_RX_BUFFER_SIZE	64
 
 /* SECTION: Console options */
+#define RT_USING_CONSOLE
 /* the buffer size of console */
 #define RT_CONSOLEBUF_SIZE	128