Rather than sprinkle casts throughout the code, change Py_CHARMASK to
always cast it's result to an unsigned char.  This should ensure we
do the right thing when accessing an array with the result.

since char is signed on some platforms and unsigned on others.

Added 0b and 0o literals to tokenizer.
Modified PyOS_strtoul to support 0b and 0o inputs.
Modified PyLong_FromString to support guessing 0b and 0o inputs.
Renamed test_hexoct.py to test_int_literal.py and added binary tests.
Added upper and lower case 0b, 0O, and 0X tests to test_int_literal.py

Fixes the tokenizer, tokenize.py and int() to reject this.
Patches by Malte Helmert.

* unified the way intobject, longobject and mystrtoul handle
  values around -sys.maxint-1.

* in general, trying to entierely avoid overflows in any computation
  involving signed ints or longs is extremely involved.  Fixed a few
  simple cases where a compiler might be too clever (but that's all
  guesswork).

* more overflow checks against bad data in marshal.c.

* 2.5 specific: fixed a number of places that were still confusing int
  and Py_ssize_t.  Some of them could potentially have caused
  "real-world" breakage.

* list.pop(x): fixing overflow issues on x was messy.  I just reverted
  to PyArg_ParseTuple("n"), which does the right thing.  (An obscure
  test was trying to give a Decimal to list.pop()... doesn't make
  sense any more IMHO)

* trying to write a few tests...

In general, C doesn't define anything about what happens when
an operation on a signed integral type overflows, and PyOS_strtol()
did several formally undefined things of that nature on signed
longs.  Some version of gcc apparently tries to exploit that now,
and PyOS_strtol() could fail to detect overflow then.

Tried to repair all that, although it seems at least as likely to me
that we'll get screwed by bad platform definitions for LONG_MIN
and/or LONG_MAX now.  For that reason, I don't recommend backporting
this.

Note that I have no box on which this makes a lick of difference --
can't really test it, except to note that it didn't break anything
on my boxes.

Silent change:  PyOS_strtol() used to return the hard-coded 0x7fffffff
in case of overflow.  Now it returns LONG_MAX.  They're the same only on
32-bit boxes (although C doesn't guarantee that either ...).

rather than longs.  This also fixes the test for eval(-sys.maxint - 1).

- update header checks, using autoconf
- provide dummies for getenv, environ, and GetVersion
- adjust MSC_VER check in socketmodule.c