RtlTimeToSecondsSince1970 - Convert system time to unix time

; #FUNCTION# ====================================================================================================================
; Name ..........: _RtlTimeToSecondsSince1970
; Description ...: Converts the specified 64-bit system time to the number of seconds since the beginning of January 1, 1970.
; Syntax ........: _RtlTimeToSecondsSince1970($_iTime[, $_hNtdll = Default])
; Parameters ....: $_iTime              - 64-bit integer specifying the time in 100 nanosecond intervals since January 1, 1601 (UTC).
;                  $_hNtdll             - [optional] Handle to an opened Ntdll.dll file
; Return values .: None
; Author ........: name22 (www.autoit.de)
; Modified ......:
; Remarks .......:
; Related .......: _NtQuerySystemTime
; Link ..........: http://msdn.microsoft.com/en-us/library/windows/desktop/ms724928%28v=vs.85%29.aspx
; Example .......: Yes
; ===============================================================================================================================
Func _RtlTimeToSecondsSince1970($_iTime, $_hNtdll = Default)
    If $_hNtdll = Default Then $_hNtdll = "Ntdll.dll"

    $_aRet = DllCall($_hNtdll, "BOOL", "RtlTimeToSecondsSince1970", "INT64*", $_iTime, "INT64*", "")
    If @error Then Return SetError(1, 0, -1)

    Return $_aRet[2]
EndFunc