'libvpx' decoder doesn't exist anymore but we continue to disable it anyway
for people building and older version

This would need more testing and close look

This needs testing

This would deserve a second look, though

This does not support hot plug and unplug of devices.

Also, it prevented selecting a device not in the choices list due to
checks in the variables subsystem. (At least with ALSA, not all valid
devices are included in the suggestions.)

Far too many bugs in this code path recently.

Using var_Set("device") is wrong: the "device" variable holds the
currently used output device (as set by the aout plugin), not the
intended output device (as requested through the user interface).

Also fix a memory leak.

If I understood correctly, drive letters are always ANSI

Weirdly, there is no GetProcAddressW, indeed

Since OutputDebugStringW is just a wrapper around OutputDebugStringA

Close #6895
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

This requires bleeding-edge libavcodec.