Issue #27778: Fix a memory leak in os.getrandom() when the getrandom() is
interrupted by a signal and a signal handler raises a Python exception.

Modify also os_getrandom_impl() to avoid the temporary buffer, use directly a
Python bytes object.

Issue #27955: Fallback on reading /dev/urandom device when the getrandom()
syscall fails with EPERM, for example when blocked by SECCOMP.

Issue #27955: Fallback on reading /dev/urandom device when the getrandom()
syscall fails with EPERM, for example when blocked by SECCOMP.

Issue #27955: modify py_getrnadom() and dev_urandom()

* Add comments from Python 3.7
* PEP 7 style: add {...}

Issue #28200: Replace PyUnicode_AsWideCharString() with
PyUnicode_AsUnicodeAndSize().

 (Patch by Xiang Zhang)

- Rename Py_ADDRESS_IN_RANGE to address_in_range and make it a static
  function instead of macro. Any compiler worth its salt will inline this
  function.
- Remove the duplicated function version of Py_ADDRESS_IN_RANGE used when memory
  analysis was active. Instead, we can simply mark address_in_range as allergic
  to dynamic memory checking. We can now remove the
  __attribute__((no_address_safety_analysis)) from _PyObject_Free and
  _PyObject_Realloc. All the badness is contained in address_in_range now.
- Fix the code that tried to only read pool->arenaindex once. Putting something
  in a variable is no guarantee that it won't be read multiple times. We must
  use volatile for that.

Issue #28195: Don't expect the fd leak message to be on a specific line number,
just make sure that the line is present in the output.

Initial patch by Peter Wirtz.

I forgot there two variations of os.stat() in Python 3.5.