FindOpenCL.cmake mismatch with the official cmake module

[ddemidov]

CMake since v3.1 includes FindOpenCL.cmake.

The problem with the one that is included with HPX is that the official module exports OpenCL_INCLUDE_DIRS and OpenCL_LIBRARIES, while HPX one exports OPENCL_INCLUDE_DIRS and OPENCL_LIBRARIES (note the difference in capitalization). Both modules export OpenCL_FOUND though, so, when a project depends both on OpenCL and HPX, different set of variables will be available, depending on which comes first in CMakeLists.txt: find_package(OpenCL) or find_package(HPX). This may lead to interesting results when one expects one or the other naming convention.

I could try and replace OPENCL_* variable names with OpenCL_* ones throughout HPX cmake files. Would that be acceptable?

[ddemidov]

Less intrusive option would be to just export both sets of variables from HPX FindOpenCL module.

[hkaiser]

Currently, none of the code in HPX depends on OpenCL. This file is an artifact, afaics. @mcopik Is that correct?

[hkaiser]

Moreover, none of the HPX cmake build system imports the FindOpenCL file. So I think it is safe to simply remove the file from HPX.

[hkaiser]

This was fixed by merging #2595

[ddemidov]

Thanks!

[mcopik]

@hkaiser Everything should be fine, CMake and SYCL have their own scripts for OpenCL. Thanks!