c3c: hotfix for darwin build

[ricardo-valero]

This fixes the build on darwin by modifying the CMakeLists.txt.

Loosely based on c3lang/c3c#1914.

This was only tested locally for aarch64-darwin.

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandboxing enabled in nix.conf? (See Nix manual)
  • sandbox = relaxed
  • sandbox = true
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 25.05 Release Notes (or backporting 24.11 and 25.05 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
• Fits CONTRIBUTING.md.

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[yzx9]

Thanks for your contribution, and welcome to nixpkgs!

However, after you created the PR, the upstream PR was updated. It seems that upstream intends to fix this issue by modifying CMakeLists.txt. Could you please check the current status of the upstream PR?

A few review comments:

• The commit should be squashed.
• The commit message can match the PR title.

For more details, please refer to the commit conventions.