Issue #26564:

* Expose _Py_DumpASCII() and _Py_DumpDecimal() in traceback.h
* Change the type of the second _Py_DumpASCII() parameter from int to unsigned
  long
* Rewrite _Py_DumpDecimal() and dump_hexadecimal() to write directly characters
  in the expected order, avoid the need of reversing the string.
* dump_hexadecimal() limits width to the size of the buffer
* _Py_DumpASCII() does nothing if the object is not a Unicode string
* dump_frame() wrtites "???" as the line number if the line number is negative

Issue #26558.

* Add Lib/test/signalinterproctester.py
* Don't disable the garbage collector anymore
* Don't use os.fork() with a subprocess to not inherit existing signal handlers
  or threads: start from a fresh process
* Don't use UNIX kill command to send a signal but Python os.kill()
* Use a timeout of 10 seconds to wait for the signal instead of 1 second
* Always use signal.pause(), instead of time.wait(1), to wait for a signal
* Use context manager on subprocess.Popen
* remove code to retry on EINTR: it's no more needed since the PEP 475
* remove unused function exit_subprocess()
* Cleanup the code

Patch from Victor van den Elzen.

Patch from Victor van den Elzen.

Issue #26558: The debug hook of PyObject_Malloc() now checks that the GIL is
held when the function is called.

Issue #10915, #15751, #26558:

* PyGILState_Check() now returns 1 (success) before the creation of the GIL and
  after the destruction of the GIL. It allows to use the function early in
  Python initialization and late in Python finalization.
* Add a flag to disable PyGILState_Check(). Disable PyGILState_Check() when
  Py_NewInterpreter() is called
* Add assert(PyGILState_Check()) to: _Py_dup(), _Py_fstat(), _Py_read()
  and _Py_write()

Fix regex for parse a pointer address.

Ignore pip warning in test_venv.test_with_venv().

Fix a warning on Windows 64-bit.

It's more to fix a conversion warning during compilation, I don't think that
Windows support current working directory larger than 2 GB ...

Issue #17758: Skip test_site if site.USER_SITE directory doesn't exist and
cannot be created.

On 32-bit system, only 4 bytes after dumped for the tail.

Pointers are formatted differently.

The first instruction of tracemalloc_add_trace() is traceback_new() which
already checks the GIL.

Issue #26558: If Py_FatalError() is called without the GIL, don't try to print
the current exception, nor try to flush stdout and stderr: only dump the
traceback of Python threads.

Issue #26558: If Py_FatalError() is called without the GIL, don't try to print
the current exception, nor try to flush stdout and stderr: only dump the
traceback of Python threads.

Issue #26516:

* Add PYTHONMALLOC environment variable to set the Python memory
  allocators and/or install debug hooks.
* PyMem_SetupDebugHooks() can now also be used on Python compiled in release
  mode.
* The PYTHONMALLOCSTATS environment variable can now also be used on Python
  compiled in release mode. It now has no effect if set to an empty string.
* In debug mode, debug hooks are now also installed on Python memory allocators
  when Python is configured without pymalloc.

in BaseHTTPRequestHandler

Initial patch by karlcow.

#25687: clarify that errors in tearDown increase the total number of reported errors.  Initial patch by HyeSoo Park.