* bpo-30871: pythoninfo: add expat and _decimal

* Remove _decimal.__version__

The string is hardcoded, not really interesting.

* Add Lib/test/pythoninfo.py: script collecting various informations
  about Python to help debugging test failures.
* regrtest: remove sys.hash_info and sys.flags from header.
* Travis CI, Appveyor: run pythoninfo before tests

Tools/scripts/patchcheck.py now ignores changes in directories which
are copies of external libraries:

* Modules/_ctypes/libffi_msvc/
* Modules/_ctypes/libffi_osx/
* Modules/_decimal/libmpdec/
* Modules/expat/
* Modules/zlib/

Drop also support for Mercurial, since CPython migrated to Git.

Exclude also libmpdec

patchcheck: exclude also libffi_osx and libffi_msvc

Change the option for `Français` into `French` to be consistent with the other language selections that are already in English.

bpo-18966: non-daemonic threads created by a multiprocessing.Process should be joined on exit (#3111)

* bpo-18966: non-daemonic threads created by a multiprocessing.Process should be joined on exit

* Add NEWS blurb

Fix a warning about dangling processes in test_rapid_restart() of
_test_multiprocessing: join the process.

* Revert "Add Bruno Penteado to ACKS (#3091)"

This reverts commit f978405b.

* Revert "bpo-30983: eval frame rename in pep 0523 broke gdb's python extension (#2803)"

This reverts commit 2e0f4db1.

  The slightly modified tests continue to pass.  Patch by Cheryl Sabella.

OpenSSL 1.1.0 to 1.1.0e aborted the handshake when server and client
could not agree on a protocol using ALPN. OpenSSL 1.1.0f changed that.
The most recent version now behaves like OpenSSL 1.0.2 again. The ALPN
callback can pretend to not been set.

See https://github.com/openssl/openssl/pull/3158 for more details
Signed-off-by: Christian Heimes <christian@python.org>

Patch by Cheryl Sabella.

pep 0523 renames PyEval_EvalFrameEx to _PyEval_EvalFrameDefault while the gdb python extension only looks for PyEval_EvalFrameEx to understand if it is dealing with a frame.

Final effect is that attaching gdb to a python3.6 process doesnt resolve python objects. Eg. py-list and py-bt dont work properly.

This patch fixes that. Tested locally on python3.6

* Make error message more informative

Replace assertions in error-reporting code with more-informative version that doesn't cause confusion over where and what the error is.

* Additional clarification + get travis to check

* Change from SystemError to TypeError

As suggested in PR comment by @pitrou, changing from SystemError; TypeError appears appropriate.

* NEWS file installation; ACKS addition (will do my best to justify it by additional work)

_Py_atomic_* are currently not implemented as atomic operations
when building with MSVC. This patch attempts to implement parts
of the functionality required.

Remove unneeded word `to`.

_test_multiprocessing now marks the test as ENV_CHANGED on dangling
process or thread.

* reap_children() now sets environment_altered to True to detect bugs
  using python3 -m test --fail-env-changed
* Replace bare "except:" with "except OSError:" in reap_children()
* Write an unit test for reap_children() using a timeout of 60
  seconds

* Add socketserver.ForkingMixIn.server_close()

bpo-31151: socketserver.ForkingMixIn.server_close() now waits until
all child processes completed to prevent leaking zombie processes.

* Fix test on Windows which doesn't have ForkingMixIn

TestRandomNameSequence.test_process_awareness() now calls
os.waitpid() to avoid leaking a zombie process.

The current test_child_terminated_in_stopped_state() function test
creates a child process which calls ptrace(PTRACE_TRACEME, 0, 0) and
then crash (SIGSEGV). The problem is that calling os.waitpid() in the
parent process is not enough to close the process: the child process
remains alive and so the unit test leaks a child process in a
strange state. Closing the child process requires non-trivial code,
maybe platform specific.

Remove the functional test and replaces it with an unit test which
mocks os.waitpid() using a new _testcapi.W_STOPCODE() function to
test the WIFSTOPPED() path.

Idlelib.calltips.get_argspec now uses inspect.signature instead of inspect.getfullargspec, like help() does.  This improves the signature in the call tip in a few different cases, including builtins converted to provide a signature.  A message is added if the object is not callable, has an invalid signature, or if it has positional-only parameters.
Patch by Louie Lu.

TestModule.test_after_fork() now calls os.waitpid() to read the exit
status of the child process to avoid creating a zombie process.

Add a post_test_cleanup() function which currently only calls
support.reap_children().

PtyTests.run_child() now calls os.waitpid() to read the exit status
of the child process to avoid creating zombie process and leaking
processes in the background.

This fix a regex issue (a missing non-matching group around an 'or'
list) and the specific possible case where a translation is built but
not yet in known by the picker, but not explicitly listing possible
languages in the regex.

bpo-31072: Add a filter argument to zipapp.create_archive (GH-3021)

* Add an include_file argument to allow callers to decide which files to include
* Document the new argument