close #7873

(first window as wallpaper, all other ones as normal windows.)

Also, omit fraction of seconds.

Fixes #7776

Signed-off-by: Felix Paul Kühne <fkuehne@videolan.org>

Fix #7884 and #7887 by implementing the first proposition.

thanks to David for the feedback

Clone and wall is not supported yet.

bug was triggered only when using controls provided by the OS like NSWindow's fullscreen button

We only considered the audio already buffered through opensles engine,
so the calculation was incorrect.

Use samples rather than bytes for calculation, and a function rather than
hardcoding 2*2 all over the place when a size in bytes is needed.

Ubuntu bug #1038303