enable indevs/outdevs build config?

[sethvincent]

I realized today that we might need to enable indev/outdev to be able to do actual device listing with the avdevice api.

I tried enabling macos devices locally by appending these args:

--enable-indev=avfoundation
--enable-outdev=audiotoolbox

But still ended up with a build that couldn't list devices. I'm not sure what I'm missing.

Enabling this wouldn't solve all device listing issues with ffmpeg as cross-platform support seems hit and miss, but it would still be useful.