PS2MBUTMASK       279 dev/pckbc/pms.c #define PS2MBUTMASK 0x04
PS2MBUTMASK       298 dev/pckbc/pms_intelli.c #define PS2MBUTMASK 0x04
PS2MBUTMASK        86 dev/usb/ums.c  #define PS2MBUTMASK	x04