changing IOError to OSError (#16715).

Fix bug in existing human test and add instructions; fix two bugs in tested
code; remove redundancies, add spaces, and change two internal method names.
Add mock_tk with mocks for tkinter.Variable subclasses and tkinter.messagebox.
Use mocks in test_config_name to unittest methods that are otherwise gui-free.

socket.gethostname() now decodes the hostname from the locale encoding, instead
of using the UTF-8 encoding in strict mode.

os.path.join(*self.dirs) produces an invalid path on windows.
ftp paths are always forward-slash seperated like this. /pub/dir.

by using the wording from the Py2.7 docs.

hostname is resolvable by socket.gethostname for local machine. This all fixes
certain freebsd builtbot failures.

towards target. This fixes a bug where target is accessible, but parent
directories are restricted.

character in _decimal.c.

This helps in handling certain types invalid urls in a conservative manner.

touchup test_idle. Rename README.txt.

is overriden with the CC environment variable, use the new compiler as
the default for linking if LDSHARED is not also overriden.  This restores
Distutils behavior introduced in 3.2.3 and inadvertently dropped in 3.3.0.

stream's read() returns more bytes than requested.

on unsuitable platform/environment.

non-alphabet characters present in the input string to conform a docstring.
Updated the module documentation.

Issue #13772: Restored directory detection of targets in `os.symlink` on Windows, which was temporarily removed in Python 3.2.3 due to an incomplete implementation. The implementation now works even if the symlink is created in a location other than the current directory.

Preliminary patch by Rajagopalasarma Jayakrishnan.

This affects pyexpat and _elementtree. PyExpat_CAPI now exposes a new
function - DefaultUnknownEncodingHandler.

Based on a patch by Serhiy Storchaka.

to interp->modules) and that deleting essential items from the dict
can cause Python to blow up.

Thanks to Terry Reedy for coming up with initial wording and Yogesh
Chaudhari for coming up with a patch using that wording in parallel to
my own patch.

Without this patch socket.getaddrinfo crashed when called
with some unusual argument combinations.

Patch by Guilherme Simões.