Make C11 default. pio should actually do this.
Make C11 default. pio should actually do this.

Signed-off-by: David Graeff <cddf4d21ffd604ccd3fdffe1267f1f9d72e179ea@web.de>

Openhab-Nodes/libWakaamaEmb,Openhab-Nodes/libWakaamaEmb,Openhab-Nodes/libWakaamaEmb,Openhab-Nodes/libWakaamaEmb