GNOME 3.20 dropped support for tap-to-click?

[Francois Gouget <fgouget@free.fr>]

Since the upgrade to GNOME 3.20.1 I lost tap-to-click in GNOME.
I cannot reestablish it in gnome-control-center as that only offers to 
switch the left and right buttons.

Does anyone know of a workaround to that?

Note that:
* xserver-xorg-input-libinput is installed.

* Tap-to-click still works in gdm3. See bug 731439:
  https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=731429

* However the same command I used for bug 731439 has no effect in my 
  GNOME session. That is:
  gdm gsettings set org.gnome.desktop.peripherals.touchpad tap-to-click true
  has no effect

* I also tried the following command with values 1 through 12 with no 
  result:
  xinput set-prop "ETPS/2 Elantech Touchpad" "Synaptics Tap Action" 1
  ('ETPS/2 Elantech Touchpad' is the name of my touchpad btw)

* I did not find anything related to tap-to-click in gnome-tweak-tools.


-- 
Francois Gouget <fgouget@free.fr>              http://fgouget.free.fr/
                            1 + e ^ ( i * pi ) = 0