add proc toFILETIME to winlean

Author: hendrikgit

lib/windows/winlean.nim

@@ -1086,3 +1086,8 @@ proc ConvertThreadToFiberEx*(param: pointer, flags: int32): pointer {.stdcall, d
 proc DeleteFiber*(fiber: pointer): void {.stdcall, discardable, dynlib: "kernel32", importc.}
 proc SwitchToFiber*(fiber: pointer): void {.stdcall, discardable, dynlib: "kernel32", importc.}
 proc GetCurrentFiber*(): pointer {.stdcall, importc, header: "Windows.h".}
+
+proc toFILETIME(unix: int64, ns: int): FILETIME =
+  let unixns = unix * 1_000_000_000 + ns
+  let win = unixns div 100 + 116444736000000000
+  result = FILETIME(dwLowDateTime: cast[DWORD](win), dwHighDateTime: DWORD(win shr 32))