ffmpeg.profile needs ld.so.cache on arch linux

[jose1711]

Arch Linux needs ld.so.cache added to private-etc in ffmpeg.profile. Otherwise it gives:

$ ffmpeg
/usr/bin/ffmpeg: error while loading shared libraries: libmfx.so.1: cannot open shared object file: No such file or directory

[rusty-snake]

Fixed, Thanks.

[rusty-snake]

@glitsj16 I pinned this issue for now, so people see it (hopefully).

[Vincent43]

The problem should be fixed in Arch Linux soon without need for changes in firejail: https://bugs.archlinux.org/task/65238 although the workarounds would be still useful to keep for similar cases in future.