#6519)

Converting with line_info=False and col_info=True crashed before.

as docstrings and translatable strings, and rejects
bytes literals and f-string expressions.

Fix clang ubsan (undefined behavior sanitizer) warnings in dictobject.c by
adjusting how the internal struct _dictkeysobject shared keys structure is
declared.

This remains ABI compatible.  We get rid of the union at the end of the
struct being used for conveinence to avoid typecasting in favor of char[]
variable length array at the end of a struct. This is known to clang to be
used for variable sized objects and will not cause an undefined behavior
problem.  Similarly, char arrays do not have strict aliasing undefined
behavior when cast.

PEP-007 does not currently list variable length arrays (VLAs) as allowed
in our subset of C99.  If this turns out to be a problem, the fix to this is
to change the char `dk_indices[]` into `dk_indices[1]` and restore the
three size computation subtractions this change removes:
  `- Py_MEMBER_SIZE(PyDictKeysObject, dk_indices)`

If this works as is I'll make a separate PR to update PEP-007.

…ILD_CORE (GH-6489)

Setup modules are no longer built with -DPy_BUILD_CORE by default,
as using that flag may now require including additional internal-only header files.

Instead, only the modules that specifically need it use that setting.

Upgrade ensurepip to bundle pip 10.0.1

Also update PIL doc references to Pillow.

This change contains minor things that make diffing between Lib/tokenize.py and
Lib/lib2to3/pgen2/tokenize.py cleaner.

Starting with glibc 2.27.9000-xxx, sigaddset() can return EINVAL for some
reserved signal numbers between 1 and NSIG.  The `range(1, NSIG)` idiom
is commonly used to select all signals for blocking with `pthread_sigmask`.
So we ignore the sigaddset() return value until we expose sigfillset()
to provide a better idiom.

#6446)

* bpo-33251: ConfigParser.items no longer returns items present in vars.

Documentation for `ConfigParser.items()` states:
'Items present in vars no longer appear in the result.'

This fix aligns behaviour to that specified in the documentation.

GH-6273)

External importers were being added in both phases of the import
system initialisation.

They're only supposed to be added in the second phase, after the
import machinery has been appropriately configured.

Cast pointer difference from ssize_t to int: a frame is very unlikely
larger than 2 GB.

…RGS. (GH-6030)

METH_NOARGS functions need only a single argument but they are cast
into a PyCFunction, which takes two arguments.  This triggers an
invalid function cast warning in gcc8 due to the argument mismatch.
Fix this by adding a dummy unused argument.