failures gracefully

Explicitly clear all elements from arena->a_objects and remove
assert() that refcount is 1.  It's possible for a program to get a
reference to the list via sys.getobjects() or via gc functions.

e.g. IndentationError. (bug #1447885)

we are about to leave behind. An example of the cause of this leak can be
found in the leakers directory, in case we ever want to tackle the
underlying problem.

module. It's possible to generate HTML calendar now and the module can be
called as a script (e.g. via ``python -mcalendar``).

regenerated codec should survive reindent.py unchanged.

IncrementalDecoder.decode().

gcc.  Without this flag, doing pretty much anything with NaNs causes
a Floating Point Exception signal.  This causes the interpreter to quit.
The failing tests this fixes are:  test_float, test_long, and test_struct.
This is somewhat equivalent to doing signal(SIGFPE, SIG_IGN).

Will verify if this is a problem in 2.4 and backport if necessary (probably).

caused detection of the error)

effect at the time test_decimal was imported.  Else
running test_decimal had the bad side effect of
permanently changing the decimal context in effect.
That caused text_tokenize to fail if it ran after
test_decimal.

- The doctests in decistmt() weren't run at all when
  test_tokenize was run via regrtest.py.

- Some expected output in decistmt() was Windows-specific
  (but nobody noticed because the doctests weren't getting
  run).

- test_roundtrip() didn't actually test anything when
  running the tests with -O.  Now it does.

- Changed test_roundtrip() to show the name of the input
  file when it fails.  That would have saved a lot of
  time earlier today.

- Added a bunch of comments.

adds the following API calls: PySet_Clear(), _PySet_Next(), and
_PySet_Update().  The latter two are considered non-public.  Tests and
documentation (for the public API) are included.

on OSX 10.4 or later. This stops the compiler for complaining about calls to
deprecated functions in these extensions, they are supposed to wrap as much
of Carbon as possible.

This is from the SF tracker as well; for some reason the
content of test_index.py was lost and an empty file was
checked in instead.

Backed out an old patch from 2000.