Closes #12192: Document that mutating list methods do not return the instance (original patch by Mike Hoy).

but without AF_CAN definition.

  (see issue 13125).

  (see issue 13125).

  with line feeds.  This was ported from the sandbox to the 3.3 branch, but
  didn't make it into 3.2.

- Re-enable lib2to3's test_parser.py tests, though with an expected failure
  (see issue 13125).

as "The pipe is being closed") is now mapped to POSIX errno EPIPE
(previously EINVAL).

as "The pipe is being closed") is now mapped to POSIX errno EPIPE
(previously EINVAL).

Improve also str.replace(a, a) test

This worked under Unix because wchar_t is 4 bytes wide.

(except for a Py_UNICODE_strchr() call)

(on Martin's buildbot it still seems a bit inaccurate)

Example:
./python -m timeit -s "f='{}' + '-' * 1024 + '{}'; s='abcd' * 16384" "f.format(s, s)"

-> before: 547 usec per loop
-> after: 13 usec per loop
-> 3.2: 22.5 usec per loop
-> 2.7: 12.6 usec per loop

contents cannot be read.

an unreadable directory.

new test cases for importing bad packages and unreadable packages dirs.