mdbx-windows: add ntdll.def for building ntdll.lib
mdbx-windows: add ntdll.def for building ntdll.lib

14 of 17 for https://github.com/leo-yuriev/libmdbx/issues/43

Change-Id: I492b4be913f0a14540e7a80b53c2a24623dfeb07

leo-yuriev/libfpta,leo-yuriev/libfpta