Also bump libdav1d and turn the wrap patches into diffs. This requires
bumping the minimum meson version to 0.63, but meson 1.0 is available
pretty much everywhere now so this should be fine.
The patched meson.build for dav1d just changes the include_directories
from 'include/dav1d' to 'include' and, while we're at it, removes the
pkg_config stuff to avoid a deprecation warning.
AV1 decoding is pretty broken in upstream ffms2, so point the wrap to a
fork that has some hack patches for it. BestSource works fine out of the
box, though.
