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)

Bug #1728403: Fix a bug that CJKCodecs StreamReader hangs when it
reads a file that ends with incomplete sequence and sizehint argument
for .read() is specified.

the traceback inadvertently or maliciously closing the comment and
injecting HTML into the error page.
 (backport from rev. 55348)

Don't use a fixed temporary name (gdbm).
Don't use our own temp name creation (dbm).

SF patch #1630975: Fix crash when replacing sys.stdout in sitecustomize

When running the interpreter in an environment that would cause it to set
stdout/stderr/stdin's encoding, having a sitecustomize that would replace
them with something other than PyFile objects would crash the interpreter.
Fix it by simply ignoring the encoding-setting for non-files.

This could do with a test, but I can think of no maintainable and portable
way to test this bug, short of adding a sitecustomize.py to the buildsystem
and have it always run with it (hmmm....)

close it.

Point users to the subprocess module in the docs for os.system, os.spawn*, os.popen2, and the popen2 and commands modules

[Bug #1542016] Report PCALL_POP value.  This makes the return value of sys.callstats() match its docstring.