Merge branch 'maint-0.4.2' into bug40076_042

changes/bug29922

-  o Minor bugfixes (testing, windows):
-    - Fix a test failure caused by an unexpected bug warning in
-      our test for tor_gmtime_r(-1). Fixes bug 29922;
-      bugfix on 0.2.9.3-alpha.

changes/bug30011

-  o Minor bugfixes (CI):
-    - Terminate test-stem if it takes more than 9.5 minutes to run.
-      (Travis terminates the job after 10 minutes of no output.)
-      Diagnostic for 29437. Fixes bug 30011; bugfix on 0.3.5.4-alpha.

changes/bug30021

-  o Minor bugfixes (TLS protocol, integration tests):
-    - When classifying a client's selection of TLS ciphers, if the client
-      ciphers are not yet available, do not cache the result. Previously,
-      we had cached the unavailability of the cipher list and never looked
-      again, which in turn led us to assume that the client only supported
-      the ancient V1 link protocol.  This, in turn, was causing Stem
-      integration tests to stall in some cases.
-      Fixes bug 30021; bugfix on 0.2.4.8-alpha.

changes/bug30040

-  o Minor bugfixes (security):
-    - Fix a potential double free bug when reading huge bandwidth files. The
-      issue is not exploitable in the current Tor network because the
-      vulnerable code is only reached when directory authorities read bandwidth
-      files, but bandwidth files come from a trusted source (usually the
-      authorities themselves). Furthermore, the issue is only exploitable in
-      rare (non-POSIX) 32-bit architectures which are not used by any of the
-      current authorities. Fixes bug 30040; bugfix on 0.3.5.1-alpha. Bug found
-      and fixed by Tobias Stoeckmann.

changes/bug30041

-  o Minor bugfixes (hardening):
-    - Verify in more places that we are not about to create a buffer
-      with more than INT_MAX bytes, to avoid possible OOB access in the event
-      of bugs.  Fixes bug 30041; bugfix on 0.2.0.16.  Found and fixed by
-      Tobias Stoeckmann.

changes/bug30148

-  o Minor bugfixes (memory leak):
-    - Avoid a minor memory leak that could occur on relays when
-      creating a keys directory failed. Fixes bug 30148; bugfix on
-      0.3.3.1-alpha.

changes/bug30189

-  o Minor bugfixes (compilation, unusual configuration):
-    - Avoid failures when building with ALL_BUGS_ARE_FAILED due to
-      missing declarations of abort(), and prevent other such failures
-      in the future. Fixes bug 30189; bugfix on 0.3.4.1-alpha.

changes/bug30190

-  o Minor bugfixes (lib):
-    do not log a warning for OpenSSL versions that should be compatible
-    Fixes bug 30190; bugfix on 0.2.4.2-alpha

changes/bug30316

-  o Minor bugfixes (directory authority):
-    - Move the "bandwidth-file-headers" line in directory authority votes
-      so that it conforms to dir-spec.txt. Fixes bug 30316; bugfix on
-      0.3.5.1-alpha.

changes/bug30452

-  o Minor features (compile-time modules):
-    - Add a --list-modules command to print a list of which compile-time
-      modules are enabled. Closes ticket 30452.

changes/bug30475

-  o Minor bugfixes ():
-    - Avoid a GCC 9.1.1 warning (and possible crash depending on libc
-      implemenation) when failing to load a hidden service client authorization
-      file.  Fixes bug 30475; bugfix on 0.3.5.1-alpha.

changes/bug30561

-  o Minor bugfixes (portability):
-    - Avoid crashing in our tor_vasprintf() implementation on systems that
-      define neither vasprintf() nor _vscprintf(). (This bug has been here
-      long enough that we question whether people are running Tor on such
-      systems, but we're applying the fix out of caution.) Fixes bug 30561;
-      bugfix on 0.2.8.2-alpha. Found and fixed by Tobias Stoeckmann.

changes/bug30713

-  o Minor bugfixes (testing):
-    - Skip test_rebind when the TOR_SKIP_TEST_REBIND environmental variable is
-      set. Fixes bug 30713; bugfix on 0.3.5.1-alpha.
-    - Skip test_rebind on macOS in Travis, because it is unreliable on
-      macOS on Travis. Fixes bug 30713; bugfix on 0.3.5.1-alpha.

changes/bug30744

-  o Minor bugfixes (continuous integration):
-    - Allow the test-stem job to fail in Travis, because it sometimes hangs.
-      Fixes bug 30744; bugfix on 0.3.5.4-alpha.

changes/bug30781

-  o Minor bugfixes (directory authorities):
-    - Stop crashing after parsing an unknown descriptor purpose annotation.
-      We think this bug can only be triggered by modifying a local file.
-      Fixes bug 30781; bugfix on 0.2.0.8-alpha.

changes/bug30894

-  o Minor bugfixes (memory leaks):
-    - Fix a trivial memory leak when parsing an invalid value
-      from a download schedule in the configuration. Fixes bug
-      30894; bugfix on 0.3.4.1-alpha.

changes/bug30916

-  o Minor bugfixes (relay):
-    - Avoid crashing when starting with a corrupt keys directory where
-      the old ntor key and the new ntor key are identical. Fixes bug 30916;
-      bugfix on 0.2.4.8-alpha.

changes/bug31003

-  o Minor bugfixes (crash on exit):
-    - Avoid a set of possible code paths that could use try to use freed memory
-      in routerlist_free() while Tor was exiting.  Fixes bug 31003; bugfix on
-      0.1.2.2-alpha.

changes/bug31107

-  o Minor bugfixes (logging, protocol violations):
-    - Do not log a nonfatal assertion failure when receiving a VERSIONS
-      cell on a connection using the obsolete v1 link protocol. Log a
-      protocol_warn instead. Fixes bug 31107; bugfix on 0.2.4.4-alpha.

changes/bug31335

+  o Minor bugfixes (code quality):
+    - Fix "make check-includes" so it runs correctly on out-of-tree builds.
+      Fixes bug 31335; bugfix on 0.3.5.1-alpha.