Initial fix attempt for a thread-related issue on Windows.

Initial fix attempt for a thread-related issue on Windows.

This is a partial fix for bug #343, which lead to a large amount of
handles being created, and eventually to a frontend "hang".

It's not yet a "full" fix as some issues are still observable,
but it successfully improves the situation on Windows to the extent
that frontend hangs due to large amounts of handles no longer seem
to happen.

Thanks to Boris Gjenero <redacted> for the debugging
efforts, testing, and updating of this patch!

Additionally, this seems to also fix a "SysClk LWLA hanging" bug
and apparently not receiving any samples during an acquisition
(tested on an LWLA1034).

This closes bug #328.