Issue #1621: Fix undefined behaviour from signed overflow in datetime module hashes, array and list iterations, and get_integer (stringlib/string_format.h)

Issue #1621: Fix undefined behaviour in bytes.__hash__, str.__hash__, tuple.__hash__, frozenset.__hash__ and set indexing operations.

Issue #13012: Allow 'keepends' to be passed as a keyword argument in str.splitlines, bytes.splitlines and bytearray.splitlines.

importing a module. Ignore the direcotry if its name matchs the module name
(e.g.  "__init__.py") and raise a ImportError instead.

module. Ignore the direcotry if its name matchs the module name (e.g.
"__init__.py") and raise a ImportError instead.

ready before having been set up.

ready before having been set up.

merge 3.2.  Fix closes issue13005 - Remove the mention of 'repeat' method in the operator module documentation.

multiprocessing.reduction, which may not be available (e.g. if the OS doesn't
support FD passing over Unix domain sockets).

multiprocessing.reduction, which may not be available (e.g. if the OS doesn't
support FD passing over Unix domain sockets).

The commit fixes 3c56e546dc60, which documented #1172711 as a struct module
change;  it is an array module change.

Initial patch by Oren Tirosh and Hirokazu Yamamoto.