MOUSE_STDBUTTONS
buf[0] = MOUSE_PS2_SYNC | butmapps2[mapped & MOUSE_STDBUTTONS];
butmapmsc[status->button & MOUSE_STDBUTTONS];
| butmap[mouse_status.button & MOUSE_STDBUTTONS];
(buttons & ~MOUSE_STDBUTTONS) |
buttonmap[sysmouse_status.button & MOUSE_STDBUTTONS];
#define MOUSE_BUTTONS (MOUSE_STDBUTTONS | MOUSE_EXTBUTTONS)
#define MOUSE_STDBUTTONSCHANGED MOUSE_STDBUTTONS