* [3.5] bpo-32563: Get expat to compile under C89

expat: Add artificial scopes in xmltok.c utf8_toUtf8() to fix c89 compilation.

Cherry-picked from libexpat commit e0b290eb3d8f4c4b45137a7d7f4f8db812145bd2

* Backport XML RPC test skip to 3.5

The buildbot service upgrade removed the XML-RPC
interface, so this test no longer works (through no
fault of the standard library).

* Don't configure a nonexistent Python

* [3.5] Remove failing pyenv call from CI config

* Backport XML RPC test skip to 3.5

The buildbot service upgrade removed the XML-RPC
interface, so this test no longer works (through no
fault of the standard library).

Fixes possible integer overflow in PyBytes_DecodeEscape.
Co-Authored-By: Jay Bosamiya <jaybosamiya@gmail.com>

(cherry picked from commit a6296d34)

* bpo-31170: Fix inclusion of expat in Windows build projects.

* Fixes line endings

* bpo-30947, bpo-31170: Update expat from 2.2.1 to 2.2.4

* Upgrade libexpat embedded copy from version 2.2.1 to 2.2.3 to get security
  fixes.

* Update libexpat from 2.2.3 to 2.2.4. Fix copying of partial
  characters for UTF-8 input (libexpat bug 115):
  https://github.com/libexpat/libexpat/issues/115

* Define XML_POOR_ENTROPY when compiling expat

Works around Travis CI bug about the python3.5 binary:
https://github.com/travis-ci/travis-ci/issues/8363

The `Show Source` was broken because of a change made in sphinx 1.5.1
In Sphinx 1.4.9, the sourcename was "index.txt".
In Sphinx 1.5.1+, it is now "index.rst.txt".
(cherry picked from commit b9ff4987)

Rather than requiring the path to blurb and/or sphinx-build to be specified to
the make rule, enhance the Doc/Makefile to look for each first in a virtual
environment created by make venv and, if not found, look on the normal process
PATH. This allows the Doc/Makefile to take advantage of an installed
spinx-build or blurb and, thus, do the right thing most of the time. Also, make
the directory for the venv be configurable and document the `make venv` target.

Use the copy provided in https://bugs.python.org/issue25910GH-msg295200
(cherry picked from commit 8474d871)
(cherry picked from commit f6306e73)

(cherry picked from commit 6fcb69da)
(cherry picked from commit 52c41f18)

* bpo-31036: use an existing Misc/NEWS rather than trying to use blurb

* bpo-31036: avoid echoing comments

(cherry picked from commit 3de14489)

(cherry picked from commit e1e60bd9)

Use the copy provided in https://bugs.python.org/issue25910GH-msg295200
(cherry picked from commit 8474d871)

(cherry picked from commit 6fcb69da)

* bpo-31036: use an existing Misc/NEWS rather than trying to use blurb

* bpo-31036: avoid echoing comments

(cherry picked from commit d5ed47de)

[3.5] [security] bpo-30119: fix ftplib.FTP.putline() to throw an error for a illegal command (#1214) (#2887)

(cherry picked from commit 39243779)

tearDown() now clears explicitly the self.server variable to make
sure that the thread is completely cleared when tearDownClass()
checks if all threads have been cleaned up.

Fix the following warning:

$ ./python -m test --fail-env-changed -m test.test_os.TestSendfile.test_keywords -R 3:1 test_os
(...)
Warning -- threading_cleanup() failed to cleanup 0 threads after 3 sec (count: 0, dangling: 2)
(...)
Tests result: ENV CHANGED
(cherry picked from commit d1cc037d)

(cherry picked from commit cfcd7677)

(cherry picked from commit 4c7532e9)

(cherry picked from commit 4da52247)

* bpo-30876: Relative import from unloaded package now reimports the package
instead of failing with SystemError.

Relative import from non-package now fails with ImportError rather than
SystemError.
(cherry picked from commit 8a9cd20e)

* bpo-18018: Import raises ImportError instead of SystemError if a relative
import is attempted without a known parent package.

* bpo-26367: importlib.__init__() raises ImportError like
builtins.__import__() when ``level`` is specified but without an accompanying
package specified.

Cython will, in the right circumstances, offer a MethodType instance
where im_func is a builtin function. Any instance of MethodType is
automatically assumed to be a Python-defined function (more
specifically, a function that has an inspectable signature), but
_set_signature was still conservative in its assumptions. As a result
_set_signature would return early with None instead of a mock since
the im_func had no inspectable signature. This causes problems
deeper inside mock, as _set_signature is assumed to _always_
return a mock, and nothing checked its return value.

In similar corner cases, autospec will simply not check the spec of the
function, so _set_signature is amended to now return early with the
original, not-wrapped mock object.

Patch by Aaron Gallagher.

(cherry picked from commit 856cbcc1)

* Oops, tzdata was introduced in Python 3.6: remove it from regrtest
* Remove also Lib/test/libregrtest/__init__.py file: add by mistake
  on a backport.

When running the test suite using --use=all / -u all, exclude tzdata
since it makes test_datetime too slow (15-20 min on some buildbots)
which then times out on some buildbots.

-u tzdata must now be enabled explicitly, -u tzdata or -u all,tzdata,
to run all test_datetime tests.

Fix also regrtest command line parser to allow passing -u
extralargefile to run test_zipfile64.

Travis CI: remove -tzdata. Replace -u all,-tzdata,-cpu with -u all,-cpu since tzdata is now excluded from -u all.
(cherry picked from commit 5b392bba)