Re: 'rx_buffer' was not declared in this scope

//=============================================================================
//======================= LCD / Controller Selection =======================
//========================= (Graphical LCDs) ========================
//=============================================================================

//
// CONTROLLER TYPE: Graphical 128x64 (DOGM)
//
// IMPORTANT: The U8glib library is required for Graphical Display!
// [github.com]
//

//
// RepRapDiscount FULL GRAPHIC Smart Controller
// [reprap.org]
//
//#define REPRAP_DISCOUNT_FULL_GRAPHIC_SMART_CONTROLLER
#define REPRAP_DISCOUNT_SMART_CONTROLLER ~THERE WAS NO SUCH OPTION I JUST ADDED IT THERE
//
// ReprapWorld Graphical LCD
// [reprapworld.com]
//
//#define REPRAPWORLD_GRAPHICAL_LCD

//
i dont even know what helps