PyImport_ExtendInittab() now uses PyMem_RawRealloc() rather than
PyMem_Realloc(). PyImport_ExtendInittab() can be called before
Py_Initialize() whereas only the PyMem_Raw allocator is supposed to
be used before Py_Initialize().

Add _PyImport_Fini2() to release the memory allocated by
PyImport_ExtendInittab() at exit. PyImport_ExtendInittab() now forces
the usage of the default raw allocator, to be able to release memory
in _PyImport_Fini2().

Don't export these functions anymore to be C API, only to
Py_BUILD_CORE:

* _PyExc_Fini()
* _PyImport_Fini()
* _PyGC_DumpShutdownStats()
* _PyGC_Fini()
* _PyType_Fini()
* _Py_HashRandomization_Fini()

* Py_Main() now starts by reading Py_xxx configuration variables to
  only work on its own private structure, and then later writes back
  the configuration into these variables.
* Replace Py_GETENV() with pymain_get_env_var() which ignores empty
  variables.
* Add _PyCoreConfig.dump_refs
* Add _PyCoreConfig.malloc_stats
* _PyObject_DebugMallocStats() is now responsible to check if debug
  hooks are installed. The function returns 1 if stats were written,
  or 0 if the hooks are disabled. Mark _PyMem_PymallocEnabled() as
  static.

Remove also the initstr variable, unused since the commit
e69f0df4 pushed in 2012: "bpo-13959:
Re-implement imp.find_module() in Lib/imp.py"

* Simplify _PyCoreConfig_INIT, _PyMainInterpreterConfig_INIT,
  _PyPathConfig_INIT macros: no need to set fields to 0/NULL, it's
  redundant (the C language sets them to 0/NULL for us).
* Fix typo: pymain_run_statup() => pymain_run_startup()
* Remove a few XXX/TODO

The undecodable file name cannot be created on macOS APFS file systems.

* Rather than raise TypeError, warn and call list() on the value.

* Fix tests, revise NEWS and whatsnew text.

* Revise documentation, a string is okay as well.

* Ensure 'requires' and 'obsoletes' are real lists.

* Test that requires and obsoletes are turned to lists.

When tk event handling is driven by IDLE's run loop, a confusing
and distracting queue.EMPTY traceback context is no longer added
to tk event exception tracebacks.  The traceback is now the same
as when event handling is driven by user code.  Patch based on
a suggestion by Serhiy Storchaka.

Patches are in 3.7.0a3 even if this update is not.

* Revert "bpo-32197: Try to fix a compiler error on OS X introduced in bpo-32030. (#4681)"

This reverts commit 13badcbc.

Re-apply commits:

* "bpo-32030: _PyPathConfig_Init() sets home and program_name (#4673)"
  commit af5a8950.
* "bpo-32030: Fix config_get_program_name() on macOS (#4669)"
  commit e23c06e2.
* "bpo-32030: Add Python/pathconfig.c (#4668)"
  commit 0ea395ae.
* "bpo-32030: Don't call _PyPathConfig_Fini() in Py_FinalizeEx() (#4667)"
  commit ebac19da.
* "bpo-32030: Fix Py_GetPath(): init program_name (#4665)"
  commit 9ac3d888.

* Fix compilation error on macOS

Also fixed searching patterns that could match an empty string.

uuid.get_node() always must return a stable result.
Also added a test for non-reproducibility of _random_getnode().
Original patch by Xavier de Gaye.

The original algorithm tried to delegate the folding to the tokens so
that those tokens whose folding rules differed could specify the
differences.  However, this resulted in a lot of duplicated code because
most of the rules were the same.

The new algorithm moves all folding logic into a set of functions
external to the token classes, but puts the information about which
tokens can be folded in which ways on the tokens...with the exception of
mime-parameters, which are a special case (which was not even
implemented in the old folder).

This algorithm can still probably be improved and hopefully simplified
somewhat.

Note that some of the test expectations are changed.  I believe the
changes are toward more desirable and consistent behavior: in general
when (re) folding a line the canonical version of the tokens is
generated, rather than preserving errors or extra whitespace.

instead of crashing due to a stack overflow.

This perhaps will fix similar problems in other extension types.

Add import_find_and_load() helper function.  The addition of
the importtime option has made PyImport_ImportModuleLevelObject() large
and so using a helper seems worthwhile.  It also makes it clearer that
abs_name is the only argument needed by _find_and_load().

Previously, CO_NOFREE was set in the compiler, which meant
it could end up being set incorrectly when code objects
were created directly. Setting it in the constructor based
on freevars and cellvars ensures it is always accurate,
regardless of how the code object is defined.

Also addresses doc build failures documented in bpo-32200.

If the marshal or bytecode formats get changed, frozen.c needs to
be updated as well.  It can be easy to miss this step and not doing
so can cause test_importlib to crash in mysterious ways.  Add an
explict unit test to make it easier to track down the problem.