synaptics: don't link the tools against `pkg-config --libs xorg-server`
synaptics: don't link the tools against `pkg-config --libs xorg-server`

Separate the checks for xserver 1.6 and for libXi in configure, so we
can link the tools against libXi but not pixman and pciaccess.

Signed-off-by: Julien Cristau <82c7ebd12259428dfee9dc86e69f3a9d6f3dccb9@debian.org>
Reviewed-by: Dan Nicholson <2570c412b7cbb4203ff39baaca2bd49e72848226@gmail.com>
Signed-off-by: Peter Hutterer <b9c50af7afa7642f6f854434cda9ffe54ece8b85@who-t.net>

mad-s/xf86-input-synaptics-absolute,mad-s/xf86-input-synaptics-absolute