Make sure we return version 0 if XInput detection fails
Backed out changeset a6493ee0c9b5
Add support for the freedesktop.org Idle Inhibition specification,
as per:
http://people.freedesktop.org/~hadess/idle-inhibition-spec/

This makes screensaver inhibition work with GNOME 3 and other
desktop environments that implement the specification.

https://bugzilla.libsdl.org/show_bug.cgi?id=2169

--HG--
extra : rebase_source : b1967a91febdaa3f0fcb311ee1909a741722e9b2