Release 2.1.1

Version 2.1.1

• Reentrant multi-threaded writing of compressed files fixed
  with 'closeform' (using 'pipe|fork|exec|closefrom') on Linux.

• New IPASIR-UP options, with the same default as in 1.1:

  • exteagerreasons where the solver eagerly asks for reasons before
    analysing conflicts instead of being lazy (default: eager)

  • exteagerrecalc where the solver recalculates the levels on the
    trail before conflict analysis (default: on). Mostly useful if
    the solver provides many propagations in a lazy fashion. Requires
    exteagerreasons to be on to have any effect.

• Fix performance regression for incremental SAT solving due to too
  eager garbage collection before any incremental call in favor of
  only doing it during variable elimination

• Fix performance regression for the SAT anniversary track.

• Slight memory usage reduction expected thanks to not allocating some
  internal array only used for proof and external propagator.

• Mobical deterministic compiled with or without logging.

• Fixed memory corruption and leaks when allocation of arena fails
  and further added support in fuzzer to trigger such bad allocations.