Don't cast directly to an __int64

http://msdn.microsoft.com/en-us/library/windows/desktop/ms724284%28v=vs.85%29.aspx
"Do not cast a pointer to a FILETIME structure to either a ULARGE_INTEGER* or
__int64* value because it can cause alignment faults on 64-bit Windows."

Based on TortoiseSVN revision 25660

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>