AF_PACKET cases in getsockaddrarg were missing their own checks for
tuple-ness of the address argument, which means a confusing SystemError was
raised by PyArg_ParseTuple instead.

The new char-array used in ioctl calls wasn't explicitly NUL-terminated;
quite probably the cause for the test_pty failures on Solaris that we
circumvented earlier. (I wasn't able to reproduce it with this patch, but it
has been somewhat elusive to start with.)

terminology in the alpha 1 documentation.

 - "context manager" reverts to its alpha 1 definition
 - the term "context specifier" goes away entirely
 - contextlib.GeneratorContextManager is renamed GeneratorContext

There are still a number of changes relative to alpha 1:

  - the expression in the with statement is explicitly called the
    "context expression" in the language reference
  - the terms 'with statement context', 'context object' or 'with
    statement context' are used in several places instead of a bare
    'context'. The aim of this is to avoid ambiguity in relation to the
    runtime context set up when the block is executed, and the context
    objects that already exist in various application domains (such as
    decimal.Context)
  - contextlib.contextmanager is renamed to contextfactory
    This best reflects the nature of the function resulting from the
    use of that decorator
  - decimal.ContextManager is renamed to WithStatementContext
    Simple dropping the 'Manager' part wasn't possible due to the
    fact that decimal.Context already exists and means something
    different. WithStatementContext is ugly but workable.

A technically unrelated change snuck into this commit:
contextlib.closing now avoids the overhead of creating a
generator, since it's trivial to implement that particular
context manager directly.

Edward Loper.

an installed VC6. Otherwise only the first such tree gets checked and this
warning doesn't get displayed.

'context specifier' in a few places

Fix broken contextlib test from last checkin (I'd've sworn I tested that before checking it in. . .)

requiring both expected output and an exception.

I'll backport to 2.4 next.

Take 2 on mentioning the with statement, this time without inadvertently killing the Unicode examples

Add a Context Types section to parallel the Iterator Types section (uses the same terminology as the 2.5a1 implementation)

This patch checks if poll is broken when the select module is loaded instead
of doing so at configure-time. This functionality is only active on Mac OS X.