Fix the logic in python-config.sh to avoid attempting to substitute
prefix in a variable that might have already been subject to
substitution. This e.g. happened if @exec_prefix@ was defined as
"${prefix}" (which is the default of the configure script) -- in which
case the exec_prefix_build variable was initialized with
already-subtituted prefix, and then another round of substitution was
performed which might have resulted in duplicate prefix.

To avoid that, rename the variables so that the variables matching
likely configure names (prefix, exec_prefix) retain their original
values and a '_real' suffix is used for the real values of prefix.

Furthermore, replace the unnecessary prefix and exec_prefix
substitutions with direct prefix_real references since the sed
always replaced the whole string anyway by design.
(cherry picked from commit 14086cfc)

Class execution requires that __prepare__() methods return
a proper execution namespace. Check for that immediately
after calling __prepare__(), rather than passing it through
to the code execution machinery and potentially triggering
SystemError (in debug builds) or a cryptic TypeError
(in release builds).

Patch by Oren Milman.
(cherry picked from commit 5837d041)

Some objects (like test mocks) auto-generate new objects on
attribute access, which can lead to an infinite loop in
inspect.unwrap().

Ensuring references are retained to otherwise temporary objects
and capping the size of the memo dict turns this case into a
conventional exception instead..
(cherry picked from commit f9169ce6)

(cherry picked from commit 236329ed)

[3.6] bpo-31505: Fix an assertion failure in json, in case _json.make_encoder() received a bad encoder() argument. (GH-3643) (#3777)

(cherry picked from commit 2b382dd6)

[3.6] bpo-31285: Fix an assertion failure and a SystemError in warnings.warn_explicit. (GH-3219) (#3775)

(cherry picked from commit 91fb0afe)

[3.6] bpo-31490: Fix an assertion failure in ctypes in case an _anonymous_ attr is defined only outside _fields_. (GH-3615) (#3774)

(cherry picked from commit 30b61b51)

[3.6] bpo-31492: Fix assertion failures in case of a module with a bad __name__ attribute. (GH-3620). (#3773)

(cherry picked from commit 6db70331)

(cherry picked from commit 31aca4bf)

[3.6] bpo-30347: Stop crashes when concurrently iterate over itertools.groupby() iterators. (GH-1557) (#3770)

(cherry picked from commit c740e4fe)

(cherry picked from commit 0e950dd2)

- Remove the second mention about the `u` prefix
- Remove the second mention about numeric literals do not include a sign
(cherry picked from commit 4a2d00cb)

Non-regression tests for the Expat 2.2.3 UTF-8 decoder bug.

(cherry picked from commit e6d9fcbb)

[3.6] bpo-31311: Fix a SystemError and a crash in ctypes._CData.__setstate__(), in case of a bad __dict__. (GH-3254) (#3743)

(cherry picked from commit 57c2561c)

(cherry picked from commit 49392c63)

[3.6] bpo-23702: Update Descriptor-HOWTO to reflect the removal of unbound methods (GH-3739) (#3742)

(cherry picked from commit 0d4497b9)

(cherry picked from commit 0bf287b6)

The dunderless functions are preferred; dunder are retained for back compatilibity.
Patch by Sanket Dasgupta.
(cherry picked from commit 5b9299d8)

[3.6] bpo-31566: Fix an assertion failure in _warnings.warn() in case of a bad __name__ global. (GH-3717) (#3730)

(cherry picked from commit 5d3e8002)

A `"` was missing from an `<a href>` tag.
(cherry picked from commit 8337239d)

Defer removing old behavior to 3.8.
Document new feature of selection_set() and friends.
(cherry picked from commit 2fad1023)

Mention that ``NewType`` can derive from another ``NewType``.
(cherry picked from commit 039b25d8)

(cherry picked from commit d6238a76)

[3.6] bpo-31459: Rename IDLE's module browser from Class Browser to Module Browser. (GH-3704) (#3710)

The original module-level class and method browser became a module
browser, with the addition of module-level functions, years ago.
Nested classes and functions were added yesterday.  For back-
compatibility, the virtual event <<open-class-browser>>, which
appears on the Keys tab of the Settings dialog, is not changed.
Patch by Cheryl Sabella.
(cherry picked from commit cd99e79d)

Order dependence caused leak-test buildbots to fail when running test_idle repeatedly.
(cherry picked from commit 99167f85)

(cherry picked from commit aecc08ac)

Original patches for code and tests by Guilherme Polo and
Cheryl Sabella, respectively.

(cherry picked from commit 058de113)

Use prefixed macro names for the `authoraddress` function, add T2A to the font encoding in LaTeX sources to support Cyrillic characters in the PDF documentation, and replace the deprecated `font_size` config option with `pointsize`.
(cherry picked from commit da9b4cfb)

Previously ensurepip would always report success, even if the
pip installation failed.
(cherry picked from commit 9adda0cd)

* Update version changed notice for backport

(cherry picked from commit a96c96f5)

Fix a memory corruption in getpath.c due to mixed memory allocators
between Py_GetPath() and Py_SetPath().

The fix use the Raw allocator to mimic the windows version.

This patch should be used from python3.6 to the current version

for more details, see the bug report and
  https://github.com/pyinstaller/pyinstaller/issues/2812
(cherry picked from commit 3d1e2ab5)

(cherry picked from commit 19e4d934)

This one line of Serhiy Storchacka's bpo-31500 patch for is needed for other issues.
(cherry picked from commit d6e2f26f)

(cherry picked from commit 9b47af65)

(cherry picked from commit 132a7d7c)

(cherry picked from commit a92941ff)

[3.6] bpo-31293: Fix crashes in truediv and mul of a timedelta by a float with a bad as_integer_ratio() method. (GH-3227) (#3654)

(cherry picked from commit 865e4b4f)

[3.6] bpo-31315: Fix an assertion failure in imp.create_dynamic(), when spec.name is not a string. (GH-3257) (#3653)

(cherry picked from commit 9974e1bc)