Closes #15925: fix regression in parsedate() and parsedate_tz() that should return None if unable to parse the argument.

Issue #15977: Fix memory leak in Modules/_ssl.c when the function _set_npn_protocols() is called multiple times

constructing infinities. This is done for backwards compatibility
with decimal.py: Infinity coefficients are undefined in _decimal
(in accordance with the specification).

Issue #15895: my analysis was slightly off. The FILE pointer is only leaked when set_main_loader() fails for a pyc file with closeit=0. In the success case run_pyc_file() does its own cleanup of the fp. I've changed the code to use another FILE ptr for pyc files and moved the fclose() to PyRun_SimpleFileExFlags() to make it more obvious what's happening.

Issue #15895: Fix FILE pointer leak in PyRun_SimpleFileExFlags() when filename points to a pyc/pyo file and closeit is false.

they are created in the install locations and with the proper timestamp.
(Solution suggested by MvL)

sporadic crashes in multi-thread programs when several long deallocator
chains ran concurrently and involved subclasses of built-in container
types.

Because of this change, a couple extension modules compiled for 3.2.4
(those which use the trashcan mechanism, despite it being undocumented)
will not be loadable by 3.2.3 and earlier. However, extension modules
compiled for 3.2.3 and earlier will be loadable by 3.2.4.

Fix window.addch() of the curses module for special characters like
curses.ACS_HLINE: the Python function addch(int) and addch(bytes) is now
calling the C function waddch()/mvwaddch() (as it was done in Python 3.2),
instead of wadd_wch()/mvwadd_wch(). The Python function addch(str) is still
calling the C function wadd_wch()/mvwadd_wch() if the Python curses is linked
to libncursesw.

return one.

This was a regression caused by the hash randomization patch.

errno error numbers and Windows error numbers.

character for most keys, and an integer for special keys, instead of always
returning an integer. So it is now possible to distinguish special keys like
keypad keys.

  compiled using the clang compiler

(merge from 3.2)