* intel: fix VA-API encoders not registering (no element "vah264enc")
The intel images fail to stream with a hardware encoder on stock config:
every client connect ends with '(pipeline error) no element "vah264enc"'.
There are three problems, all of which are needed to fix it:
1. The render group never reaches the neko process. supervisord resolves the
supplementary groups of each program from /etc/group when it spawns it, but
'rendergroup-init' (which calls usermod) is spawned in the same pass, so the
neko process usually starts before the group has been assigned and cannot
access /dev/dri/render*. Assign the group in an entrypoint, before
supervisord starts, instead.
2. libva does not initialize the X11 display without an explicitly selected
driver in this image, it fails with 'vaGetDriverNames() failed'. Set
LIBVA_DRIVER_NAME=iHD, which is the only driver installed by the intel image.
3. GStreamer only registers the VA-API elements if a usable VA display is found
while the plugins are scanned for the first time, and the outcome is cached
in the user's registry. neko performs that scan at startup, before the X
server is ready, so the cache ends up without vah264enc/vah264dec and stays
that way. Wait for VA to be usable and drop the stale registry before
starting neko.
* intel: keep the wrapper and the supervisord override in the intel image
Per the review on #721: no wrapper in every flavour with a runtime 'vainfo'
check, it should only be in the intel image.
- neko-serve moved to runtime/intel/neko-serve and is copied only by
Dockerfile.intel. The 'command -v vainfo' check is dropped, only the intel
image ships it.
- The [program:neko] block is overridden with runtime/intel/supervisord.neko.conf,
copied to /etc/neko/supervisord/neko.conf. [include] is parsed after the main
config and the last definition of a program wins, so supervisord.conf keeps
'neko serve' and it does not have to be touched. Same mechanism as
supervisord.nvidia.conf in the app images.
- runtime/supervisord.conf, runtime/Dockerfile and runtime/Dockerfile.nvidia are
back to their previous content.