LTTng: fix build script

Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>
thorium: optimize the code that pulls from the ring

The new bottleneck is in worker. I will add tracepoints in worker.

thorium_message:actor_send: (+0.000320582)
thorium_message:worker_send: (+0.000002220)
thorium_message:worker_enqueue_message: (+0.000000932)
thorium_message:worker_publish_message: (+0.000001792)
thorium_message:worker_pool_dequeue: (+0.000107388)
thorium_message:node_send: (+0.000001038)
thorium_message:node_send_system: (+0.000000891)
thorium_message:node_send_dispatch: (+0.000000716)
thorium_message:node_dispatch_message: (+0.000000848)
thorium_message:worker_pool_enqueue: (+0.000000938)
thorium_message:worker_enqueue_inbound_message: (+0.000002183)
thorium_message:worker_receive: (+0.000250567)
thorium_message:actor_receive: (+0.007543410) <=====

Signed-off-by: Sébastien Boisvert <boisvert@anl.gov>