lcd_change_fil_state has two extern's in Marlin.h, only one needed.

Firmware/Marlin.h

@@ -350,7 +350,6 @@ extern unsigned long t_fan_rising_edge;
 extern bool mesh_bed_leveling_flag;
 extern bool mesh_bed_run_from_menu;
 
-extern int8_t lcd_change_fil_state;
 // save/restore printing
 extern bool saved_printing;
 extern uint8_t saved_printing_type;