Bugzilla bug #5518: in _PR_MD_LSEEK and _PR_MD_LSEEK64, map the NSPR seek flags to the Win32 seek flags before passing them to SetFilePointer.  Simplified the code in _PR_MD_LSEEK64.
Bugzilla bug #5518: in _PR_MD_LSEEK and _PR_MD_LSEEK64, map the
NSPR seek flags to the Win32 seek flags before passing them to
SetFilePointer.  Simplified the code in _PR_MD_LSEEK64.

makotokato/nsprpub,makotokato/nsprpub,makotokato/nsprpub,makotokato/nsprpub,makotokato/nsprpub