OpenCL userspace driver as provided in the amdgpu-pro driver stack and
intended to work along with the free amdgpu stack.  It's a repackage
of AUR opencl-amd and don't provide the full amdgpu-pro stack.

The Ubuntu 18.04 drivers can be downloaded using:

/usr/bin/wget --referer https://support.amd.com/en-us/kb-articles/Pages/AMDGPU-PRO-Driver-for-Linux-Release-Notes.aspx -N https://drivers.amd.com/drivers/linux/19.50/amdgpu-pro-19.50-967956-ubuntu-18.04.tar.xz
