D7154: Only require Qt5X11Extras when we actually need it

[Volker Krause]

vkrause created this revision.
Restricted Application added a project: Frameworks.

REPOSITORY
  R274 KIdleTime

BRANCH
  master

REVISION DETAIL
  https://phabricator.kde.org/D7154

AFFECTED FILES
  CMakeLists.txt

To: vkrause, #frameworks