Merge branch 'maint-0.4.2' into bug40076_042

changes/bug28454

-  o Minor bugfixes (continuous integration, Windows):
-    - Manually configure the zstd compiler options, when building using
-      mingw on Appveyor Windows CI. The MSYS2 mingw zstd package does not
-      come with a pkg-config file. Fixes bug 28454; bugfix on 0.3.4.1-alpha.

changes/bug28485

-  o Minor bugfixes (compilation):
-    - Add missing dependency on libgdi32.dll for tor-print-ed-signing-cert.exe
-      on Windows. Fixes bug 28485; bugfix on 0.3.5.1-alpha.

changes/bug28524

-  o Minor bugfixes (restart-in-process, boostrap):
-    - Add missing resets of bootstrap tracking state when shutting
-      down (regression caused by ticket 27169).  Fixes bug 28524;
-      bugfix on 0.3.5.1-alpha.

changes/bug28525

-  o Minor features (address selection):
-    - Make Tor aware of the RFC 6598 (Carrier Grade NAT) IP range, which is the
-      subnet 100.64.0.0/10. This is deployed by many ISPs as an alternative to
-      RFC 1918 that does not break existing internal networks. This patch fixes
-      security issues caused by RFC 6518 by blocking control ports on these
-      addresses and warns users if client ports or ExtORPorts are listening on
-      a RFC 6598 address. Closes ticket 28525. Patch by Neel Chauhan.

changes/bug28554

-  o Minor bugfixes (unit tests, guard selection):
-    - Stop leaking memory in an entry guard unit test. Fixes bug 28554;
-      bugfix on 0.3.0.1-alpha.

changes/bug28562

-  o Minor bugfixes (testing):
-    - Use a separate DataDirectory for the test_rebind script.
-      Previously, this script would run using the default DataDirectory,
-      and sometimes fail. Fixes bug 28562; bugfix on 0.3.5.1-alpha.
-      Patch from Taylor R Campbell.

changes/bug28568

-  o Minor bugfixes (testing):
-    - Stop running stem's unit tests as part of "make test-stem". But continue
-      to run stem's unit and online tests during "make test-stem-full".
-      Fixes bug 28568; bugfix on 0.2.6.3-alpha.

changes/bug28569

-  o Minor bugfixes (unit tests, directory clients):
-    - Mark outdated dirservers when Tor only has a reasonably live consensus.
-      Fixes bug 28569; bugfix on 0.3.2.5-alpha.

changes/bug28612

-  o Minor bugfixes (windows services):
-    - Make Tor start correctly as an NT service again: previously it
-      was broken by refactoring.  Fixes bug 28612; bugfix on 0.3.5.3-alpha.
-      

changes/bug28619

-  o Minor bugfixes (hidden service v3):
-    - When deleting an ephemeral onion service (DEL_ONION), do not close any
-      rendezvous circuits in order to let the existing client connections
-      finish by themselves or closed by the application. The HS v2 is doing
-      that already so now we have the same behavior for all versions. Fixes
-      bug 28619; bugfix on 0.3.3.1-alpha.

changes/bug28656

-  o Minor bugfixes (logging):
-    - Stop logging a BUG() warning when tor is waiting for exit descriptors.
-      Fixes bug 28656; bugfix on 0.3.5.1-alpha.

changes/bug28698

-  o Minor bugfix (logging):
-    - Avoid logging about relaxing circuits when their time is fixed.
-      Fixes bug 28698; bugfix on 0.2.4.7-alpha

changes/bug28895

-  o Minor bugfixes (usability):
-    - Stop saying "Your Guard ..." in pathbias_measure_{use,close}_rate()
-      as that confusingly suggests that mentioned guard node is under control
-      and responsibility of end user, which it is not. Fixes bug 28895;
-      bugfix on Tor 0.3.0.1-alpha.

changes/bug28920

-  o Minor bugfixes (logging):
-    - Rework rep_hist_log_link_protocol_counts() to iterate through all link
-      protocol versions when logging incoming/outgoing connection counts. Tor
-      no longer skips version 5 and we don't have to remember to update this
-      function when new link protocol version is developed. Fixes bug 28920;
-      bugfix on 0.2.6.10.

changes/bug28938

-  o Minor bugfixes (compilation):
-    - Fix missing headers required for proper detection of
-      OpenBSD.  Fixes bug 28938; bugfix on 0.3.5.1-alpha.
-      Patch from Kris Katterjohn.

changes/bug28974

-  o Minor bugfixes (compilation):
-    - Fix compilation for Android by adding a missing header to
-      freespace.c.  Fixes bug 28974; bugfix on 0.3.5.1-alpha.

changes/bug28979

-  o Minor bugfixes (documentation):
-    - Describe the contents of the v3 onion service client authorization
-      files correctly: They hold public keys, not private keys. Fixes bug
-      28979; bugfix on 0.3.5.1-alpha. Spotted by "Felixix".

changes/bug28981

-  o Minor bugfixes (misc):
-    - The amount of total available physical memory is now determined
-      using the sysctl identifier HW_PHYSMEM (rather than HW_USERMEM)
-      when it is defined and a 64-bit variant is not available.  Fixes
-      bug 28981; bugfix on 0.2.5.4-alpha.  Patch from Kris Katterjohn.

changes/bug28995

-  o Minor bugfix (IPv6):
-    Fix tor_ersatz_socketpair on IPv6-only systems.  Previously,
-    the IPv6 socket was bound using an address family of AF_INET
-    instead of AF_INET6.  Fixes bug 28995; bugfix on 0.3.5.1-alpha.
-    Patch from Kris Katterjohn.

changes/bug29017

-  o Minor bugfixes (stats):
-    - When ExtraInfoStatistics is 0, stop including PaddingStatistics in
-      relay and bridge extra-info documents. Fixes bug 29017;
-      bugfix on 0.3.1.1-alpha.