Libinput

libinput is an input device driver for Wayland compositors and X.org window system. It is a drop-in replacement for the slowly deprecating evdev and synaptics input drivers. It provides device detection, device handling, input device event processing and abstraction so minimize the amount of custom input code compositors need to provide the common set of functionality that users expect.

USE flags
Add to the  INPUT_DEVICES  variable:

After the update the packages and  should be installed.

Additional software
Actions gestures on the touchpad using the libinput driver.

Follow the install notes from the official project page LIBINPUT-GESTURES on GitHub.

Install dependencies:

Xorg
Next the Xorg configuration must be updated to use the file. Copy the file to the directory:

Finally, restart the X server or reboot the system.

External resources

 * Latest API documentation
 * Gentoo forums discussion on libinput