Defines starting with `f' in linuxdoom

• FASTDARK src/p_spec.h:178
• FATSPREAD src/p_enemy.c:1349
• FB src/wi_stuff.c:285
• FLOORSPEED src/p_spec.h:600
• FRICTION src/p_mobj.c:112
• FUZZOFF src/r_draw.c:260
• FUZZTABLE src/r_draw.c:259