[bug#42067] [PATCH] gnu: darktable: Add optional dependencies.

[Ludovic Courtès]

Hi Vinicius,

Vinicius Monego <monego@posteo.net> skribis:

>> BTW, why are we building with Clang?
>> 
>
> This was briefly discussed in the version update thread (2020-
> 06/msg00651). To be more descriptive:

Oh sorry, I have overlooked that.

> DT 3+ requires GCC/Clang 8+ and will fail to build with the default GCC
> 7.5.0. We have to load a newer version of GCC, or use Clang. Marius
> attempted to build it with gcc-9 and "ran into other problems" although
> I have succesfully built DT3 with the same compiler and version a while
> ago.
>
> Meanwhile, DT's CMakeLists.txt checks for LLVM to enable "test-
> compilation of OpenCL programs". If LLVM is not found, this test-
> compilation is skipped. If LLVM is found, it checks for Clang, and the
> required opencl header is located inside Clang's directory. Because we
> "have to have" Clang this way, it made more sense to me to compile with
> it.
>
> Anyways, OpenCL is optional. To build with GCC only, we would have to
> load the gcc module and skip the test-compilation. It may be possible
> to use both gcc and clang, but that would add redundancy.

What’s the “test-compilation of OpenCL programs”?  Are we just talking
about the test suite?

Either way, I guess my main points are (1) it’d be nice to add a comment
on why we’re using Clang, and (2) if we can use GCC instead, that should
be our default choice.  I’m not saying we should address this right
away, but we should keep it in mind.

Thanks,
Ludo’.