Fix futhark build on Darwin

[jacereda]

Motivation for this change

Futhark won't build on Darwin and there's duplication (obsolete non-hackage package).

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Assured whether relevant documentation is up to date
• Fits CONTRIBUTING.md.

---

[peti]

👍

[basvandijk]

Thanks. The following runs successfully on my Mac Book Pro:

$(nix-build -A haskellPackages.futhark)/bin/futhark --version
Futhark 0.8.1
git: UNKNOWN @ UNKNOWN (UNKNOWN)
Copyright (C) DIKU, University of Copenhagen, released under the ISC license.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

[infinisil]

Can it compile anything on Darwin though? Just run through the first example on https://futhark-lang.org/examples.html

And what was the error on Darwin?

[jacereda]

Works for me with the OpenCL backend. Keep in mind you need to pass arguments on stdin.

[infinisil]

Odd, because the wrapping thing is not present at all on Darwin now, no idea how it can still work.

[jacereda]

I don't know what you mean, can you elaborate?

[infinisil]

The line in this PR makes it such that on Darwin it uses the unwrapped Futhark package. The wrapping logic under that line will only be applied on non-Darwin. And I added that logic down there to make compiling work, because it didn't work if it wasn't wrapped properly.

[jacereda]

Have you tried it on Darwin? What's the error?

[infinisil]

Um, I thought you were on Darwin, because I asked earlier whether it worked on Darwin and you replied that it does..

[jacereda]

I'm on Darwin and it does work for me, I was just asking if it was different for you.

The wrapper isn't needed on Darwin. There's no ocl-icd and everything should be available through OpenCL.framework.

[infinisil]

Oh I see, no I'm not on darwin.

@jacereda Do you have gcc or clang in your PATH though? Because that's another thing the wrapper does for you. Try compiling a Futhark program with export PATH="" beforehand

[jacereda]

It's finding impure dependencies, it will run if you leave /usr/bin in the path.

[infinisil]

Yeah but we don't want impure dependencies in Nix. If somebody doesn't have gcc/clang installed, the program should still run.