Several internal data structures have been reimplemented and are now skip-list based
in combination with POSIX rwlocks and atomics for fastest concurrent access
(during reads and updates). Technically, this requires the presence of libatomic.so
and stdatomic.h (which excludes some of the older Linux distributions).
BalanceNG now focuses solely on modern Linuxes and does no longer compile on
other platforms (like Solaris and macOS).