/etc/X11/xorg.conf.d/10-evdev.conf

Section "InputClass"
        Identifier "evdev touchpad catchall"
        MatchIsTouchpad "on"
        MatchDevicePath "/dev/input/event*"
        Driver "synaptics"
        Option  "EmulateTwoFingerMinZ"  "40"
        Option  "EmulateTwoFingerMinW"  "8"
        Option  "VertEdgeScroll"        "on"
        Option  "HorizEdgeScroll"       "on"
        Option  "VertTwoFingerScroll"   "on"
        Option  "HorizTwiFingerScroll"  "on"
        Option  "TapButton1"            "1"
        Option  "TapButton2"            "2"
        Option  "TapButton3"            "3"
        Option  "CircularScrolling"     "on"
        Option  "CircScrollTrigger"     "2"
EndSection