[Pkg-opencl-devel] OpenCL architectures

[Rebecca N. Palmer]

Non-portable packages are required to fail to build on architectures 
where they can't work ( 
https://www.debian.org/doc/manuals/developers-reference/ch05.en.html#packages-arch-specific 
).  A build-dependency automatically does that (e.g. nodejs is arch:any, 
libv8 isn't), but one can't build-depend on virtual packages.

A third option would be

Architecture: any
Build-Depends: pocl-opencl-icd [!armhf !kfreebsd-i386]

which would also allow running the test suite (pocl is the CPU ICD, and 
hence the only one likely to work on a buildd).

(Not sure whether including ppc64el is allowed, as main can't depend on 
non-free)