[xine-lib/f31] (8 commits) ...Disable currently missing features on EL8

Summary of changes: 51c72b8... Fix typo from 1c7f3de (*) 0f881d0... New snapshot (*) 5c613af... Enable libpng based video decoder (*) a840425... Add version to BR: where relevant (*) d3601fd... Conditionally add XvMC support back (*) 10afe2f... Enable libdav1d based video decoder (F31+) (*) 51fad32... Rework features enablement (*) 6a24a42... Disable currently missing features on EL8 (*) (*) This commit already existed in another branch; no separate mail sent