DirectSound Host API leaks the streaming thread handle

[Etienne Dechamps]

This code:

portaudio/src/hostapi/dsound/pa_win_ds.c

Line 109 in 18a606e

 #undef CLOSE_THREAD_HANDLE /* as per documentation we don't call CloseHandle on a thread created with _beginthreadex */ 

Is incorrect - the official docs suggest the opposite:

when you use _beginthreadex and _endthreadex, you must close the thread handle by calling the Win32 CloseHandle API

This means DirectSound will leak a thread handle on every stream. This can be confirmed empirically by looking at the process Win32 handle list in e.g. Process Explorer.

I already have a fix for this in #922.