Hello, Guix Help! I am not able to use tap on my touchpad. Scroll is working, mouse motion is working, left and right buttons are working, but tap and double click are not working on my touchpad.

As described in the Internet need to use /etc/X11/xorg.conf.d/90-synaptics.conf. 
But GuixSD has own filesystem structure, so there is no /etc/X11.

Here it is configuration file xorg.scm: https://git.savannah.gnu.org/cgit/guix.git/tree/gnu/packages/xorg.scm?id=v0.15.0-2564-g38a2f5eaf#n2564 <https://git.savannah.gnu.org/cgit/guix.git/tree/gnu/packages/xorg.scm?id=v0.15.0-2564-g38a2f5eaf#n2564>

I assume xorg configurations ought to be done. Please, how to write my config.scm?