GitLab

- generic user-level threading shim layer
- script 'configure2.sh' to patch Makefile for libfibre
- dedicated set of worker pthreads; optional cpu-core affinity
- support for multiple libfibre clusters, default disabled
- re-enable stop-the-world hash table expansion
- re-enable application-level timeout mechanism
- re-enable stats aggregation
- disable mutex for thread-local stats
- re-introduce 'nreqs' yielding parameter

- remove stop_threads() and related code
- disable assoc_expand() -> hash table cannot grow