xcbuild: fix interactive applications run by xcrun

[midchildan]

Fixes #358795. Commands like nix develop .#hello -c /usr/bin/git log now works normally.

❯ nix develop .#hello -c /usr/bin/python3 -c 'import os; import sys; print(os.isatty(sys.stdout.fileno()))'
True

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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[midchildan]

ping @NixOS/darwin-core

[toonn]

Not fluent in C++ but the intent is correct AFAIU.

[emilazy]

Sorry for not getting to this sooner; the change looks reasonable, thanks.

[judofyr]

Would it be possible to backport this to 24.11?

[nixos-discourse]

This pull request has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/best-practices-for-expo-react-native-development-with-devenv/58776/6