Add the 'monetary' parameter to format_string so that all
uses of format can be converted to format_string.  Adjust
the documentation accordingly, and add a deprecation
warning when format is used.

bpo-19824
bpo-20314
bpo-12518

The presence of the ``--enable-optimizations`` flag is indicated by the
value of ``$enableval``, but the configure script was checking ``$withval``,
resulting in the ``--enable-optimizations`` flag being effectively ignored.

Instead have gcc be used for the coverage build so gcc is exercised in at least one place.

bpo-23890: unittest.TestCase.assertRaises() now manually breaks a
reference cycle to not keep objects alive longer than expected.

* DOC: clarify documentation for `round`

Clarified that `round` can take a negative value for *ndigits*.

* DOC: remove trailing whitespace in previous commit

remove trailing whitespace in previous commit

Make also minor PEP8 coding style fixes on modified imports.

* Remove unused test file

* Remove duplicated text in sndhdrdata README

Since functions in the os module support path-like objects, explicit
converting Path to str no longer needed.

Now general path-like objects are supported, not just pathlib.Path.

Fast paths in partial.__new__ no longer needed since concatenating with empty
tuple was optimized.

In a future versions of Python this can be an error.

when the OS gives priority to errors such as EACCES over EEXIST.

* bpo-29861: release references to multiprocessing Pool tasks

Release references to tasks, their arguments and their results as soon
as they are finished, instead of keeping them alive until another task
arrives.

* Comments in test

permission bits of newly-created intermediate-level directories.

* Fix `make tags` warnings

`make tags` target tries to find C sources and headers in "Grammar" and
"Mac" folders and generates these warnings:

    ctags: Warning: cannot open source file "Grammar/*.[ch]" : No such file or directory
    ctags: Warning: cannot open source file "Mac/*.[ch]" : No such file or directory

This commit changes $SRCDIRS variable in configure.ac to remote these
directories. This variable is used only for tags generation.

Also, "configure" was regenerated with `autoreconf`.

* Fix `make tags` fail on non-default tag names

When ctags overrides default tags filename (e.g. `-f .tags`) `make tags`
is failed because it assumes to see default `tags` filename:

    sort: cannot read: tags: No such file or directory

This commit explicitly specifies "tags" filename for tags generation.

There was few cases of using literal 0 instead of NULL in the context of
pointers.  While this was a legitimate C code, using NULL rather than 0 makes
the code clearer.

* bpo-6532: Make the thread id an unsigned integer.

From C API side the type of results of PyThread_start_new_thread() and
PyThread_get_thread_ident(), the id parameter of
PyThreadState_SetAsyncExc(), and the thread_id field of PyThreadState
changed from "long" to "unsigned long".

* Restore a check in thread_get_ident().

* Provide socket.TCP_NOTSENT_LOWAT
* New TCP option available on recent MacOS and Linux.
* Document addition of TCP_NOTSENT_LOWAT