+LTTng 0.168 makes periodic flush energy-efficient, adds cpu idle notifiers for
+x86_32, x86_64 to deal with periodic flush vs idle interaction (other
+architectures are todo). Also fix a ltt-relay-vfs file close bug, increase
+default vm_state channel subbuffer size, fix ltt-ascii so it compiles after
+cleanup (ltt-ascii is still experimental, will need to be adapted to new
+periodic flush scheme).<br>