to better describe the signed vs unsigned return value behavior on
different platforms and versions of python. Mention the workaround to
make them all return the same thing by using & 0xffffffff.
Fixes issue4903.
Also needs to be merged into release26-maint, release30-maint, & py3k.
regardless of the native sizeof(long) used in the integer object.
This somewhat odd behavior of returning a signed is maintained in 2.x for
compatibility reasons of always returning an integer rather than a long object.
Fixes Issue1202 for Python 2.6