las3_pub / predictable_parallel_patterns

Older CMAKE versions wont work with export targets in different directories. For now we simply add the context_switcher manually to the export target of pls.

The project is currently really messy and there are sporadic sigsevs. This indicates that we still have a race in our code. Thread Sanitizer does not work with our current implementation, as it needs annotations for fibers.

The next step is to clean up the project and maybe add thread sanitizer support to our fiber implementation. This should help finding the remaining bugs.