I just noticed xf86-input-synaptics and -evdev on my test machine, probably because meta/conf/machine/include/x86-base.inc says so. I believe upstream has considered libinput the default for a while, we should probably follow the lead. This should be for Yocto 2.3, and may require tweaking the driver priorities (so default is libinput only but evdev and synaptics are preferred _if_ someone does install them).
Related: http://who-t.blogspot.com/2016/08/new-xserver-driver-sort-order.html
commit 0cdbd2ad94bf10651877058ea6f3c21df914a165 Author: Jussi Kukkonen <jussi.kukkonen@intel.com> Date: Wed Oct 26 12:14:26 2016 +0300 conf: Remove legacy X input drivers xf86-input-libinput is RRECOMMENDed by xserver-xorg, these legacy drivers are not needed. (From meta-yocto rev: 715f72d7842b4a789a78e7889b2f01cd41f02df8) commit 85d1d268585962b4175e52f0bf9800727ef0a48b Author: Jussi Kukkonen <jussi.kukkonen@intel.com> Date: Wed Oct 26 11:37:39 2016 +0300 xserver-xf86-config: Remove legacy drivers from xorg.conf Trying to configure evdev and mouse leads to errors in X startup because xf86-input-libinput is now the default. No configuration should be needed: xf86-input-libinput should just work out-of-the-box. (From OE-Core rev: bd1e0b50af7a0b08bb57cc684afaee1ca2a03545) commit a1668c8721709f3d1bc0078737514111e1985bdd Author: Jussi Kukkonen <jussi.kukkonen@intel.com> Date: Wed Oct 26 11:37:38 2016 +0300 conf: Use xf86-input-libinput by default Don't install legacy X input drivers for any machines by default, RRECOMMEND xf86-input-libinput instead. This is the setup suggested by upstream: install only libinput by default, but let niche legacy drivers sort higher in configuration so they get chosen if installed. So the order is: evdev < libinput < (synaptics|vmmouse|...) This also removes vmmouse X driver from the qemu config. If a VMware virtual mouse device really needs to be supported, we should enable CONFIG_MOUSE_PS2_VMMOUSE in kernel instead: that is directly supported by the libinput X driver. Fixes [YOCTO #10195]. (From OE-Core rev: 2d005faff6341a81a2afae28860101ba9db51ae8)