[bug#46113] [PATCH] gnu: obs: Update obs to fb347c.

[Andrew Tropin]

> I patched obs here [1]. I checked the upstream patch, and noticed that
> it ammends AddExtraModulePaths function. With Guix the list of plugin
> directories will contain *two* locations with the very same plugins,
> one with the obs store and guix-profile, hence obs will print
> 'Duplicate library?' warning messages.

It's very true, obs, will have same plugins in load paths twice, but
from what I found the problem will happen only during shutdown of obs,
when it will try to unload the same plugin twice, which doesn't affect
runtime anyhow. I had a small workaround for that (a separate
envirnoment variable, which toggles the loading of plugins from
INSTALL_PREFIX), but during review one of obs mantainers said that it's
an adhoc solution and better to solve this problem in general. The
comment from @kkartaltepe and related changes [fn:1].

The other solution was to check if OBS_PLUGINS_PATH is present and ommit
loading of builtin plugins in that case, but it will break in case
someone wants to specify just additional plugin load path (some non-guix
use case).

I decided to go without any fix to that problem as it is not directly
related to changeset I proposed and doesn't affect runtime, but it's
probably a good idea to report double free on shutdown issue to
upstream.

* Footnotes

[fn:1] https://github.com/obsproject/obs-studio/pull/4067