Fixes some mistakes and misleadings in the quote function docstring:
- reserved chars are never actually used by quote code, unreserved chars are
- reserved chars were wrong and incomplete
- mentioned that use-case is not minimal quoting wrt. RFC, but cautious quoting

Fix time.mktime() error handling on AIX for year before 1970.

Other changes:

* mktime(): rename variable 'buf' to 'tm'.
* _PyTime_localtime():

  * Use "localtime" rather than "ctime" in the error message
    (specific to AIX).
  * Always initialize errno to 0 just in case if localtime_r()
    doesn't set errno on error.
  * On AIX, avoid abs() which is limited to int type.
  * EINVAL constant is now always available.

[bpo-36146](https://bugs.python.org/issue36146) introduced another regression. In case of missing OpenSSL
libraries or headers, setup.py no longer reported _hashlib and _ssl to
be missing.
Signed-off-by: Christian Heimes <christian@python.org>



https://bugs.python.org/issue36577

dash_R() function of libregrtest doesn't call support.gc_collect()
directly anymore: it's already called by dash_R_cleanup().

Call dash_R_cleanup() before starting the loop.

python-config --ldflags no longer includes flags of the LINKFORSHARED
variable. The LINKFORSHARED variable must only be used to build
executables.

https://bugs.python.org/issue36544

https://bugs.python.org/issue34139

Fix reference leak hunting in regrtest: compute also deltas (of
reference count, allocated memory blocks, file descriptor count)
during warmup, to ensure that everything is initialized before
starting to hunt reference leaks.

Other changes:

* Replace gc.collect() with support.gc_collect()
* Move calls to read memory statistics from dash_R_cleanup() to
  dash_R()
* Pass regrtest 'ns' to dash_R()
* dash_R() is now more quiet with --quiet option (don't display
  progress).
* Precompute the full range for "for it in range(repcount):" to
  ensure that the iteration doesn't allocate anything new.
* dash_R() now is responsible to call warm_caches().

While Windows exposes the system processor queue length, the raw value
used for load calculations on Unix systems, it does not provide an API
to access the averaged value. Hence to calculate the load we must track
and average it ourselves. We can't use multiprocessing or a thread to
read it in the background while the tests run since using those would
conflict with test_multiprocessing and test_xxsubprocess.

Thus, we use Window's asynchronous IO API to run the tracker in the
background with it sampling at the correct rate. When we wish to access
the load we check to see if there's new data on the stream, if there is,
we update our load values.

Move all documentation regarding the readinto method into either io.RawIOBase or io.BufferedIOBase.

Corresponding changes to documentation in the _pyio.py module.

It turns out doing socket.listen(0) does not equal to "choose a
reasonable default". It actually means "set backlog to 0".
As such set backlog=None as the default for socket.create_server.
Fixes the following BB failures:
https://github.com/python/cpython/pull/11784#issuecomment-481036369
Ref. BPO-1756, GH-11784.

Fix reference hunting (``python3 -m test -R 3:3``) when Python has no
built-in abc module: fix _get_dump() reimplementation of libregrtest.

* Properly handle SyntaxErrors in Python source files.

SyntaxErrors in the target module will rise normally, while SyntaxErrors in dependencies will be added to badmodules. This includes a new regression test.

* Fix name collision bug.

This fixes an issue where a "fromlist" import with the same name as a previously failed import would be incorrectly added to badmodules. This includes a new regression test.

* Replace mutable default values.

Bound empty lists have been replaced with the "if param is None" idiom.

* Replace deprecated imp usage.

Constants imported from imp have been moved to private module-level constants, and ModuleFinder.find_module has been refactored to use importlib. Other than an improvement on how frozen builtin imports are reported (as the frozen imports they are, rather than the stdlib modules they *may* have originated from), these changes maintain complete compatibility with past versions... including odd behavior for returning relative (below current directory, but not a C extension) vs. absolute (above current directory, or a C extension) paths.

Patch by Brandt Bucher.

The shutil archive creation helpers use the default tarfile format,
so that API is also switching to use `pax` by default.

Remove names from the "unimplemented interfaces" list
in the minidom docs that are actually implemented. 

* No need to chunking for now.
* No need to partial read caused by EINTR for now.

Add missing `program` argument to asyncio.create_subprocess_exec documentation.

Use fewer iterations instead of iterating over the whole entry table.

Initialize init_utf8_mode earlier to fix a compiler warning.

The error messages in the parser module are referring to numeric IDs for the nodes. To improve readability, use the node names when reporting errors.