No support for SEGGER RTT STDIO

[anaoum]

It would be nice to be able to use SEGGER RTT as an STDIO driver in the the pico-sdk.

The main advantages of RTT over semihosting are the speed of data transfer and not halting execution.

RTT is widely used and even has support in OpenOCD.

[peterharperuk]

Closing this as it's been done. Add the following to your cmake file...

pico_enable_stdio_rtt(hello_serial 1)

Or change the default.

cmake .. -DPICO_STDIO_RTT=1 -DPICO_STDIO_UART=0