mmap_move_method is not 64-bit safe, and fails on the
following code:

from mmap import mmap
f = open('test.out', 'ab+')
f.write('ABCDEabcde')
f.flush()
m = mmap(f.fileno(), 10)
m.move(5, 0, 5)
m.read(10)

To fix this, mmapmodule.c:538 needs to use "LLL:move"
instead of "iii:move" (this also fixes #1921169, which
changed it from "iii" to "III").

This is in both Python 2.3 and 2.4.