Structured Exception Handling on windows.

  using the same sys.flags as the current process.
Backport from default branch.

- Issue #17477: Update the bsddb module to pybsddb 5.3.0, supporting
  db-5.x, and dropping support for db-4.1 and db-4.2.

  db-5.x, and dropping support for db-4.1 and db-4.2.

when it needs support from timemodule (which is a .so on linux):
link in timemodule.c for the required functions.

I have no idea how one would write a test for this.

Patch by July Tikhonov.

time function on non-windows isn't quite simple.

 (WSAEWOULDBLOCK - A non-blocking socket operation could not be completed
 immediately)

specifically addresses a stack misalignment issue on x86 and issues on
some more recent platforms.

Original patch by Kushal Das.

the sentence referred to. Make other minor edits to improve flow.

objects.  Original patch by Aman Shah.

#17368: Fix an off-by-one error in the Python JSON decoder that caused a failure while decoding empty object literals when object_pairs_hook was specified.

as reported by Serhiy Storchaka and Matthew Barnett.

as reported by Serhiy Storchaka and Matthew Barnett.

found by Serhiy Storchaka and Matthew Barnett