fex: init at 2410

[andre4ik3]

Adds FEX, a fast usermode x86 and x86-64 emulator for Arm64 Linux.

NOTE: When compiling with tests (doCheck = true), FEX requires a kernel with 4k page size. So this means, e.g. running it directly on something like the 16k page size Asahi kernel won't work (it will cause a <jemalloc>: Unsupported system page size error when compiling). So for testing I used an aarch64 virtual machine.

To-Do

• Package tests (currently WIP, using checkPhase)

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• 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/)
• 24.11 Release Notes (or backporting 23.11 and 24.05 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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[Liamolucko]

I have a derivation for FEX 2408 with working tests over here, if you wanted to use that for reference: https://github.com/Liamolucko/nix-config/blob/31ae4e3240addc81fd79afb4344050619f639813/pkgs/fex/default.nix