While technically a purely internal change, bpo-31845 was
a fairly significant externally visible bug caused by
these changes (environment variable based configuration
was being ignored due to a change in the relative order
of reading the environment and reading command line settings,
and the test suite was only testing the command line options)

Hence this note to essentially say "If you see odd startup
problems in 3.7 that you've never seen in previous releases,
it's probably our fault, so let us know, and we'll fix it".

This speeds up it to 20-40%.

* bpo-21423: Add an initializer argument to {Process,Thread}PoolExecutor

* Fix docstring

* Using ifconfig on NetBSD and OpenBSD.
* Using arp on Linux, FreeBSD, NetBSD and OpenBSD.

Based on patch by Takayuki Shimizukawa.

bpo-31936

All Blake2 params have to be encoded in little-endian byte order. For
the two multi-byte integer params, leaf_length and node_offset, that
means that assigning a native-endian integer to them appears to work on
little-endian platforms, but gives the wrong result on big-endian. The
current libb2 API doesn't make that very clear, and @sneves is working
on new API functions in the GH issue above. In the meantime, we can work
around the problem by explicitly assigning little-endian values to the
parameter block.

See https://github.com/BLAKE2/libb2/issues/12.

Bug report and patch by Jeroen Demeyer.

* bpo-31310: multiprocessing's semaphore tracker should be launched again if crashed

* Avoid mucking with process state in test.
Add a warning if the semaphore process died, as semaphores may then be leaked.

* Add NEWS entry

* bpo-31308: If multiprocessing's forkserver dies, launch it again when necessary.

* Fix test on Windows

* Add NEWS entry

* Adopt a different approach: ignore SIGINT and SIGTERM, as in semaphore tracker.

* Fix comment

* Make sure the test doesn't muck with process state

* Also test previously-started processes

* Update 2017-08-30-17-59-36.bpo-31308.KbexyC.rst

* Avoid masking SIGTERM in forkserver.  It's not necessary and causes a race condition in test_many_processes.

When a single .c file contains several functions and/or methods with
the same name, a safety _METHODDEF #define statement is generated
only for one of them.

This fixes the bug by using the full name of the function to avoid
duplicates rather than just the name.

Support PYTHONPROFILEIMPORTTIME envvar equivalent to -X importtime

Add METH_STACKLESS to prevent future collisions.

* bpo-28643: Record profile-opt build progress with stamp files

The profile-opt makefile target is expensive to build. Since the
makefile does not contain complete dependency information for this
target, much extra work can get done if the build is interrupted and
re-started.  Even running "make" a second time will result in a huge
amount of redundant work.

As a minimal fix (rather than removing recursive "make" and adding a
proper dependency graph), split the profile-opt target into parts:

- ensure tree is clean (profile-clean-stamp)
- build with profile generation enabled (profile-gen-stamp)
- run task to generate profile information (profile-run-stamp)
- build optimized Python using above information (profile-opt)

We use "stamp" files to record completion of the steps.  Running
"make clean" will not remove the profile-run-stamp file.

Other minor changes:

- remove the "build_all_use_profile" target.  I don't expect callers
  of the makefile to use this target so that should be safe.

- remove execution of "profile-removal" at end of "profile-opt".  I
  don't see any reason to not to keep the profile information, given
  the cost to generate it.  Removing the "profile-run-stamp" file
  will force re-generation of it.

Add new time functions:

* time.clock_gettime_ns()
* time.clock_settime_ns()
* time.monotonic_ns()
* time.perf_counter_ns()
* time.process_time_ns()
* time.time_ns()

Add new _PyTime functions:

* _PyTime_FromTimespec()
* _PyTime_FromNanosecondsObject()
* _PyTime_FromTimeval()

Other changes:

* Add also os.times() tests to test_os.
* pytime_fromtimeval() and pytime_fromtimeval() now return
  _PyTime_MAX or _PyTime_MIN on overflow, rather than undefined
  behaviour
* _PyTime_FromNanoseconds() parameter type changes from long long to
  _PyTime_t

Add new clock identfiers:

* time.CLOCK_BOOTTIME
* time.CLOCK_PROF
* time.CLOCK_UPTIME

Skip a test for unget_wch()/get_wch() on OpenBSD since they are broken
in ncurses 5.7.

[asyncio] bpo-30423: add regression test for orphan future causes "RuntimeError: Event loop stopped before Future completed." (#3295)

* call remove_done_callback in finally section

* [asyncio] bpo-30423 bug: add regression test for orphan future causes "RuntimeError: Event loop stopped before Future completed."

Replace occurence of nested comments in blake2 reference implementation
with preprocessor directive for disabling unused code.

`blake2s-load-xop.h` is conditionally pulled in only on chips with XOP
support, among others the AMD Bulldozer. The malformed comments in the
source file breaks the build of `hashlib`'s `_blake2` on GCC 6.3.0.

Official reference code on github uses `#if` so this change should be
uncontroversial.

Modify the code to use ncurses is_pad() instead of checking WINDOW
_flags field.  If your platform does not provide the is_pad(), the
existing way that checks the field will be enabled.

Note: This change does not drop support for platforms where do not
have both WINDOW _flags field and is_pad().

bpo-31910: test_create_connection() now catchs also EADDRNOTAVAIL to
fix the test on Travis CI.

Cleanup pymalloc:

* Rename _PyObject_Alloc() to pymalloc_alloc()
* Rename _PyObject_FreeImpl() to pymalloc_free()
* Rename _PyObject_Realloc() to pymalloc_realloc()
* pymalloc_alloc() and pymalloc_realloc() don't fallback on the raw
  allocator anymore, it now must be done by the caller
* Add "success" and "failed" labels to pymalloc_alloc() and
  pymalloc_free()
* pymalloc_alloc() and pymalloc_free() don't update
  num_allocated_blocks anymore: it should be done in the caller
* _PyObject_Calloc() is now responsible to fill the memory block
  allocated by pymalloc with zeros
* Simplify pymalloc_alloc() prototype
* _PyObject_Realloc() now calls _PyObject_Malloc() rather than
  calling directly pymalloc_alloc()

_PyMem_DebugRawAlloc() and _PyMem_DebugRawRealloc():

* document the layout of a memory block
* don't increase the serial number if the allocation failed
* check for integer overflow before computing the total size
* add a 'data' variable to make the code easiler to follow

test_setallocators() of _testcapimodule.c now test also the context.

Document the following functions:

* PyObject_Malloc()
* PyObject_Calloc()
* PyObject_Realloc()
* PyObject_Free()

Fix also PyMem_RawFree() documentation.

* Fix a compilation error on FreeBSD.
* Fix the data attribute size on Mac OS X.

Write the name of each subtest on a new line to help debugging when
a test does crash Python.

bpo-31897: Convert unexpected errors when read bogus binary plists into InvalidFileException. (#4171)

Removed a code that incorrectly detected in-place resizing in realloc()
 and wrote to freed memory.