configure: Try gstreamer audio backend if pulse is not available
configure: Try gstreamer audio backend if pulse is not available

Disable audio if no backend is available and configure is used with
the option '--with-audio=auto'

fgouget/spice-gtk,flexVDI/spice-gtk,SPICE/spice-gtk,SPICE/spice-gtk,fgouget/spice-gtk,flexVDI/spice-gtk,SPICE/spice-gtk,fgouget/spice-gtk,SPICE/spice-gtk