virtual/opencl: new version
One, instead of pulling in various OpenCL runtimes, only depend on
an OpenCL ICD loader (dev-libs/ocl-icd, with dev-libs/opencl-icd-loader
to be added later) in order to provide hardware-independent header
files and libraries for OpenCL-aware software to build against.
Actual runtimes are now simply suggested to the user via a postinst
message / README.gentoo file.
Two, do not depend on eselect-opencl either - both ICD loaders pull in
their own OpenCL headers so there is no need to depend on the legacy
headers provided by this package, and for being able to switch to a
specific loader it is enough for loaders themselves to depend on this.
Signed-off-by: Marek Szuba <marecki@gentoo.org>