The openfp functions of aifp, sunau, and wave had pointed to the open
function of each module since 1993 as a matter of backwards
compatibility. In the case of aifc.openfp, it was both undocumented
and untested. This change begins the formal deprecation of those
openfp functions, with their removal coming in 3.9.

This additionally adds a TODO in test_pyclbr around using aifc.openfp,
though it shouldn't be changed until removal in 3.9.

* Fix compilation of the socket module on NetBSD 8.
* Fix the assertion failure or reading arbitrary data when parse
  a AF_BLUETOOTH address on NetBSD and DragonFly BSD.
* Fix other potential errors and make the code more reliable.

* Silence error output in test_concurrent_futures (bpo-21423)

kB (*kilo* byte) unit means 1000 bytes, whereas KiB ("kibibyte")
means 1024 bytes. KB was misused: replace kB or KB with KiB when
appropriate.

Same change for MB and GB which become MiB and GiB.

Change the output of Tools/iobench/iobench.py.

Round also the size of the documentation from 5.5 MB to 5 MiB.

async and await keywords has been merged into upstream, but they are
all missing in the lexical analysis docs. This change adds them to the
appropriate keywords section in documentation.

Py_UNUSED has a public name, and is used in the wild outside CPython,
but was not documented. Rectify that.

The macro was added in bpo-19976 and referenced in bpo-26179.

The macro was added for bpo-31338 in commit b2e57948

* bpo-21862: Add -m option to cProfile for profiling modules

It looks like this was copied from one of the previous tests, which did use it.

* bpo-31970: Reduce performance overhead of asyncio debug mode.

* fix doc for multiprocessing.connection.Client

The authenticate argument does not exist on either Client or Listener:
- https://github.com/python/cpython/blob/master/Lib/multiprocessing/connection.py#L483 (master)
- https://github.com/python/cpython/blob/3.6/Lib/multiprocessing/connection.py#L478 (3.6)
- https://github.com/python/cpython/blob/3.5/Lib/multiprocessing/connection.py#L478 (3.5)
- https://github.com/python/cpython/blob/3.4/Lib/multiprocessing/connection.py#L487 (3.4)
The documentation also claimed that these functions will call `current_process().auth_key`, for which I could find no evidence in the code. I rewrote the documentation to reflect the actual behavior.

Also made some small changes to vary sentence structure.

By accident the size of the empty dict keys object matched the
size of values array.

Few bytes at the begin and at the end of the reallocated blocks, as well
as the header and the trailer, now are erased before calling realloc()
in debug build.  This will help to detect using or double freeing the
reallocated block.