o Major bugfixes (parsing):
    - Fix an integer underflow bug when comparing malformed Tor versions.
      This bug is harmless, except when Tor has been built with
      --enable-expensive-hardening, which would turn it into a crash;
      or on Tor 0.2.9.1-alpha through Tor 0.2.9.8, which were built with
      -ftrapv by default.
      Part of TROVE-2017-001. Fixes bug 21278; bugfix on
      0.0.8pre1. Found by OSS-Fuzz.