Issue #4469: Prevent expandtabs() on string and unicode
objects from causing a segfault when a large width is passed
on 32-bit platforms.

Backport of r67266

  segfault as a result. CVE-2008-4864.

backport r66689

  parameter but was not verifying that it was greater than zero.  Values
  less than zero will now raise a SystemError and return NULL to indicate a
  bug in the calling C code. CVE-2008-1887.

  backport r62261, r62271

  conditions in the PyOS_vsnprintf C API function. CVE-2008-3144.

  zlib.decompressobj().flush(val) when val is not positive.

  overflows in the imageop and rgbimgmodule modules.

to the signed max value similar to 2.5 and trunk.

Issue #2620: Overflow checking when allocating or reallocating memory
was not always being done properly in some python types and extension
modules.  PyMem_MALLOC, PyMem_REALLOC, PyMem_NEW and PyMem_RESIZE have
all been updated to perform better checks and places in the code that
would previously leak memory on the error path when such an allocation
failed have been fixed.

Added checks for integer overflows, contributed by Google. Some are
only available if asserts are left in the code, in cases where they
can't be triggered from Python code.

problems:
52448, 52468, 52472, 52475, 52646, 52797, 52802, 52863, 52999, 53001,
53101, 53371, 53373, 53383, 53384, 53736, 53812, 53921, 55578, 55580,
55581, 55772, 55775, 56557, 57093, 57094, 58630, 60114

- Issue #1336: fix a race condition in subprocess.Popen if the garbage
  collector kicked in at the wrong time that would cause the process
  to hang when the child wrote to stderr.

- be more strict about the build environment
- update some of the 3th party libraries (later patchlevels)