With the Windows 8.1 SDK, the v1 of the AUDCLNT_STREAMOPTIONS enum is
defined which only has NONE and RAW, so it's not only defined when
AudioClient3 is available.
Add a meson check for the symbol. This is not needed for Autotools
because there we build against the MinGW audioclient.h which is still
at v1 of the AudioClient interface.
This allows us to request ultra-low-latency device periods even in
shared mode. However, this requires good drivers and Windows 10, so
we only enable this when we detect that we are running on Windows 10
at runtime.
You can forcibly disable this feature on Windows 10 by setting
GST_WASAPI_DISABLE_AUDIOCLIENT3=1 in the environment.