Add click method libinput option (#1416)

<libinput>
  <device>
    <clickMethod>none|buttonAreas|clickfinger</clickMethod>
  </device>
</libinput>

docs/labwc-config.5.scd

@@ -592,6 +592,7 @@ extending outward from the snapped edge.
     <dragLock></dragLock>
     <middleEmulation></middleEmulation>
     <disableWhileTyping></disableWhileTyping>
+    <clickMethod></clickMethod>
   </device>
 </libinput>
 ```
@@ -667,6 +668,22 @@ extending outward from the snapped edge.
 	any motion events while a keyboard is typing, and for a short while
 	after as well.
 
+*<libinput><device><clickMethod>* [none|buttonAreas|clickfinger]
+	Configure the method by which physical clicks on a touchpad are mapped to
+	mouse-button events.
+
+	The click methods available are:
+	- *buttonAreas* - The bottom of the touchpad is divided into distinct
+	  regions corresponding to left, middle and right buttons; clicking within
+	  the region will trigger the corresponding event. Clicking the main area
+	  further up produces a left button event.
+	- *clickfinger* - Clicking with one, two or three finger(s) will produce
+	  left, right or middle button event without regard to the location of a
+	  click.
+	- *none* - Physical clicks will not produce button events.
+
+	The default method depends on the touchpad hardware.
+
 ## WINDOW RULES
 
 Two types of window rules are supported, actions and properties. They are

docs/rc.xml.all

@@ -465,13 +465,14 @@
     non-touch, default or the name of a device. You can obtain device names by
     running *libinput list-devices* as root or member of the input group.
 
-    Tap is set to *yes* be default. All others are left blank in order to use
+    Tap is set to *yes* by default. All others are left blank in order to use
     device defaults.
 
     All values are [yes|no] except for:
       - pointerSpeed [-1.0 to 1.0]
       - accelProfile [flat|adaptive]
       - tapButtonMap [lrm|lmr]
+      - clickMethod [none|buttonAreas|clickfinger]
   -->
   <libinput>
     <device category="default">
@@ -485,6 +486,7 @@
       <dragLock></dragLock>
       <middleEmulation></middleEmulation>
       <disableWhileTyping></disableWhileTyping>
+      <clickMethod></clickMethod>
     </device>
   </libinput>