o Minor fixes (threads, comments):
    - Fix an incorrect comment on spawn_func in compat_pthreads.c.
      spawn_func calls pthread_create on unix, not fork
      Patch by "teor".
      Bugfix on unknown tor version (existing code split out of
      compat.c into compat_pthreads.c in c2f0d52b7fb9 on 22 Sep 2013).