fix: kcms/input and kcms/touchpad should not be built if XInput is not present.

Review Request #126014 - Created Nov. 10, 2015 and submitted - Latest diff uploaded

Johan Ouwerkerk

Previously the presence of evdev headers would enable the kcms/input KCM module, and the presence of synaptics driver headers would enable the touchpad module.
However, both KCMs unconditionally depend on XInput in some way in a (sub) CMakelists.txt file and deliberately break the build if it is not present or not properly detected.

As per the convention in the KCM modules shipped by plasma-desktop, inclusion of the kcms/input and kcms/touchpad subdirectory is made conditional on XInput being present and properly detected during the cmake configure stage.

This patch can be pulled from the fix-cmake-xinput-dep branch at:

Built without XInput development files, using kdesrc-build.