Log Message:
tor: Update to 0.4.2.6

Changes:
0.4.2.6
-------
  This is the second stable release in the 0.4.2.x series. It backports
  several bugfixes from 0.4.3.1-alpha, including some that had affected
  the Linux seccomp2 sandbox or Windows services. If you're running with
  one of those configurations, you'll probably want to upgrade;
  otherwise, you should be fine with 0.4.2.5.

  o Major bugfixes (linux seccomp sandbox, backport from 0.4.3.1-alpha):
    - Correct how we use libseccomp. Particularly, stop assuming that
      rules are applied in a particular order or that more rules are
      processed after the first match. Neither is the case! In
      libseccomp <2.4.0 this lead to some rules having no effect.
      libseccomp 2.4.0 changed how rules are generated, leading to a
      different ordering, which in turn led to a fatal crash during
      startup. Fixes bug 29819; bugfix on 0.2.5.1-alpha. Patch by
      Peter Gerber.
    - Fix crash when reloading logging configuration while the
      experimental sandbox is enabled. Fixes bug 32841; bugfix on
      0.4.1.7. Patch by Peter Gerber.

  o Minor bugfixes (correctness checks, backport from 0.4.3.1-alpha):
    - Use GCC/Clang's printf-checking feature to make sure that
      tor_assertf() arguments are correctly typed. Fixes bug 32765;
      bugfix on 0.4.1.1-alpha.

  o Minor bugfixes (logging, crash, backport from 0.4.3.1-alpha):
    - Avoid a possible crash when trying to log a (fatal) assertion
      failure about mismatched magic numbers in configuration objects.
      Fixes bug 32771; bugfix on 0.4.2.1-alpha.

  o Minor bugfixes (testing, backport from 0.4.3.1-alpha):
    - When TOR_DISABLE_PRACTRACKER is set, do not apply it to the
      test_practracker.sh script. Doing so caused a test failure. Fixes
      bug 32705; bugfix on 0.4.2.1-alpha.
    - When TOR_DISABLE_PRACTRACKER is set, log a notice to stderr when
      skipping practracker checks. Fixes bug 32705; bugfix
      on 0.4.2.1-alpha.

  o Minor bugfixes (windows service, backport from 0.4.3.1-alpha):
    - Initialize the publish/subscribe system when running as a windows
      service. Fixes bug 32778; bugfix on 0.4.1.1-alpha.

  o Testing (backport from 0.4.3.1-alpha):
    - Turn off Tor's Sandbox in Chutney jobs, and run those jobs on
      Ubuntu Bionic. Turning off the Sandbox is a work-around, until we
      fix the sandbox errors in 32722. Closes ticket 32240.
    - Re-enable the Travis CI macOS Chutney build, but don't let it
      prevent the Travis job from finishing. (The Travis macOS jobs are
      slow, so we don't want to have it delay the whole CI process.)
      Closes ticket 32629.

  o Testing (continuous integration, backport from 0.4.3.1-alpha):
    - Use zstd in our Travis Linux builds. Closes ticket 32242.