Re: 'rx_buffer' was not declared in this scope

BUT the thing is that they have listed
THIS #define REPRAP_DISCOUNT_FULL_GRAPHIC_SMART_CONTROLLER AM I GONA BUY THIS?
BUT I HAVE THIS #define REPRAP_DISCOUNT_SMART_CONTROLLER

i tried Putting #define REPRAP_DISCOUNT_SMART_CONTROLLER BUT same thing AgiN