New comment by st3r4g on void-packages repository

https://github.com/void-linux/void-packages/issues/21899#issuecomment-629127980

Comment:
This is not really about mesa specifically.
A user has no reason to install `mesa-opencl` (or any other implementation of an API) alone by itself, unless he wants to do OpenCL development (in this case he should know he needs the loader too). Let's say instead someone wants to use an OpenCL-powered application: he will install that application, which links to the loader, therefore automatically getting the loader as a dependency. The simplest possible example of such an app is `clinfo`. Then you run `clinfo`, which says there are no actual OpenCL implementations in your system. They can't be automatically provided, because we don't know the hardware configuration (or needs of a certain impl) of the user. It is at this point that the user must make a choice: let's say he has an AMD card, so he goes for `mesa-opencl`. Or maybe the soon-to-be-packaged ROCm. Or both. `ocl-icd` is already there, pulled in by the actual application the user is trying to run.