Not sure if this is updated recently but here is a list https://wiki.openmandriva.org/en/Packages_forcing_gcc_use

That list is definitely out of date, because it still references the old ABF instance...

Amazing news :)

So VAAPI support can soon land in Firefox for Linux? Cool. This is great news for me.

Can you give us some details? When? Can I somehow help in testing, for example in Firefox nightly? What hardware can be supported? What formats, h264 or/and vp9?

We can't promise anything yet, sorry, but we are looking into it.