For historical reference, Ulf has pointed out that I misunderstood what
was going on here, and this diff is incorrect.
There is a much more elegant way of handling this with xorg.conf that he
pointed out using separate InputClasses with MatchIsTouchPad and
MatchIsPointer options.
Thanks Ulf, and
I was having an issue where I was unable to separately define
sensitivity and acceleration on my X1. When the touchpad is usable, the
trackpoint is borderline unusable (the opposite is also true). xinput
was showing:
$ xinput list
⎡ Vir