Variables starting with `z' in quakeworld

• zbuffer quakeworld/client/vid_null.c:12
• zi16stepu quakeworld/client/d_varsa.asm:277
• zi8stepu quakeworld/client/d_varsa.asm:278
• ziscale quakeworld/client/r_alias.c:45
• zombietime quakeworld/server/sv_main.c:42
• zspantable quakeworld/client/d_modech.c:30