Bug#682397: darktable: recommend opencl package

[Tino Mettler]

Hi,

10 years later, the situation doesn't have changed much.  At least for
AMD and NVidua GPUs, you need vendor packages from external sources to
use OpenCL and get a performance gain.  In the current state, the
rusticl OpenCL implementation, which is part of Mesa, seems to lack
features and/or is still too buggy.  At least it can not be used for
darktable and AMD support has to be enabled by setting an environment
variable.

This is a general issue that the darktable package can not change.  So
I propose to close this bug.

Regards,
Tino