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.
Define MAXPATHLEN to be at least PATH_MAX, if that's defined. Python uses
MAXPATHLEN-sized buffers for various output-buffers (like to realpath()),
and that's correct on BSD platforms, but not Linux (which uses PATH_MAX, and
does not define MAXPATHLEN.) Cursory googling suggests Linux is following a
newer standard than BSD, but in cases like this, who knows. Using the
greater of PATH_MAX and 1024 as a fallback for MAXPATHLEN seems to be the
most portable solution.
SF bug #1251300: On UCS-4 builds the "unicode-internal" codec will now complain
about illegal code points. The codec now supports PEP 293 style error handlers.
(This is a variant of the patch by Nik Haldimann that detects truncated data)
