audiofile: fix build with clang 16

[viraptor]

Description of changes

std::unary_function is removed in c++17
This breaks building with clang 16. (#234710)

Things done

Set the -std to a lower one.

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandbox = true set in nix.conf? (See Nix manual)
• 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/)
• 23.11 Release Notes (or backporting 23.05 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.

[toonn]

Fixes the issue on x86_64-darwin. However, I can't reproduce the failure on x86_64-linux.
Any idea why that might be? I would assume Clang 16 on Linux still defaults to C++17?

[toonn]

LGTM

The lack of failure on x86_64-linux without these fixes is due to libstdc++ opting to implement those classes for ABI stability apparently.