kratz00's Wiki

http://xorg.freedesktop.org/archive/individual/driver/xf86-input-synaptics-1.2.0.tar.bz2

For use with kernel 2.6.x you need to enable synaptics touchpad support when configuring the kernel (CONFIG_MOUSE_PS2). You also need support for the evdev interface (CONFIG_INPUT_EVDEV).
If you compile evdev as a module, make sure it is loaded before starting the X server, as it will not be auto-loaded.

export XORG_PREFIX="/usr" &&
export XORG_CONFIG="--prefix=$XORG_PREFIX --sysconfdir=/etc \
    --mandir=$XORG_PREFIX/share/man --localstatedir=/var"

./configure $XORG_CONFIG --with-xorg-module-dir=$XORG_PREFIX/lib/X11/modules &&
make

make install

Add the driver to the Xorg configuration file (usually called /etc/X11/xorg.conf)

Section "Module"
...
 Load "synaptics"
...
EndSection

also this

 Section "InputDevice"
  Driver        "synaptics"
  Identifier    "TouchPad"
  Option        "Protocol"      "auto-dev"
  Option        "LeftEdge"      "1700"
  Option        "RightEdge"     "5300"
  Option        "TopEdge"       "1700"
  Option        "BottomEdge"    "4200"
  Option        "FingerLow"     "25"
  Option        "FingerHigh"    "30"
  Option        "MaxTapTime"    "180"
  Option        "MaxTapMove"    "220"
  Option        "VertScrollDelta" "100"
  Option        "MinSpeed"      "0.06"
  Option        "MaxSpeed"      "0.12"
  Option        "AccelFactor" "0.0010"
 EndSection

and not to forget I changed the “ServerLayout” section, so I can use the mouse if connected or the touchpad if enabled or both at the same time

 Section "ServerLayout"
        Identifier     "X.org Configured"
        Screen      0  "Screen0" 0 0
        InputDevice    "TouchPad" "CorePointer"
        InputDevice    "Mouse0" "SendCoreEvents"
        InputDevice    "Keyboard0" "CoreKeyboard"
 EndSection