To resolve a compatibility problem found with py2exe and
pywin32, imp.load_dynamic() once again ignores previously loaded modules
to support Python modules replacing themselves with extension modules.

Patch by Petr Viktorin.

The concept of .pyo files no longer exists. Now .pyc files have an
optional `opt-` tag which specifies if any extra optimizations beyond
the peepholer were applied.

multiple times.

Issue #7732: try to fix test_bug7732's flakiness on Windows by executing it in a fresh temporary directory.

To make sure there is no issue with code that is both Python 2 and 3
compatible, there are no plans to remove the module any sooner than
Python 4 (unless the community moves to Python 3 solidly before then).

test_imp.

legitimately false.

Windows.

trying to load an extension module.

While at it, also add a proper unittest.skipIf() guard to another test
involving imp.load_dynamic().

Patch by Václav Šmilauer.

return one.

return one.

NotimplementedError when sys.implementation.cache_tag is None.

Thanks to Pranav Ravichandran for taking an initial stab at the patch.

importlib.abc.FileLoader.load_module()/get_filename() and
importlib.machinery.ExtensionFileLoader.load_module() have their
single argument be optional as the loader's constructor has all the
ncessary information.

This allows for the deprecation of
imp.load_source()/load_compile()/load_package().

semantics.

in Python/dynload_shlibs.c.

This should fix the remaining importlib test failure on Windows.
Support in AIX and HP-UX will be in a separate checkin.

#14629 changed the message.

We don't need to create a temporary buffered binary or text file object just to
create an empty file.

Replace also os.fdopen(handle).close() by os.close(handle).