Switch to POCL

[vchuravy]

The outstanding

• [x] POCL@v7 https://github.com/JuliaGPU/KernelAbstractions.jl/pull/599
• [ ] printf support https://github.com/JuliaGPU/KernelAbstractions.jl/pull/592
• [ ] Switch to pocl_standalone https://github.com/JuliaPackaging/Yggdrasil/pull/11166
  • Renaming issue in build
• [ ] Distentagle SPIRVIntrinsics: Currently we inherit quirks from OpenCL https://github.com/JuliaGPU/KernelAbstractions.jl/blob/main/src/pocl/device/quirks.jl but this uses the same method table as OpenCL
• [ ] Test OpenCL and KA together to ensure that we have no hidden conflicts.
  • [ ] Downstream CI ala #608
• [ ] Float16 support
  • https://github.com/JuliaGPU/KernelAbstractions.jl/pull/609
  • https://github.com/JuliaGPU/OpenCL.jl/issues/312

cc: @maleadt