[arch-general] Open Source ati driver can't load GLX extension

[Jesse Juhani Jaara]

> Is there a possibility to add llvm to the dependencies of xf86-video-ati ?
> 
> I'm having llvm in my ignorepackages and it doesn't get updated, so 
> xf86-video-ati should not have been updated as far as I see.

llvm is depency for mesa, and as we usually don't use versioned
depencies for packages in Arch, as everything is expected to be updated
and cherry picking is frowned uppon. So even if you have llvm in ignore
list, packages that depend on it will still get updated, as they assume
you also update llvm....