QtMobility's approach to inhibit the screensaver on Maemo wakes up the screen every thirty seconds. This makes it impossible to activate the screen saver by the user.
Work around it by just asking not to do automatic screen blanking periodically.

Previously the plugin was only compiled when QtMobility was found. Now that dependency is gone, but you need to enable its compilation explicitly using the BUILD_INHIBIT_SCREENSAVER_PLUGIN cmake option.

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