Consider enable libdav1d

[davepiar]

I would consider enable the dav1d decoder since it seems to be the best for AV1 decoding.

This would be the enable option: --enable-libdav1d

I don't know if this is easy to compile in the container.

Thanks in advance!

[saudet]

Sure! Contributions are welcome

[davepiar]

Can you please give me some hint? I've looked arround but I still don't undersand how the build process works. Where should I add this flag?

[saudet]

In the cppbuild.sh script