nodejs: fix cross compilation for non-emulatable platforms

[rhelmot]

This was tested x86_64-linux -> x86_64-freebsd. It works by injecting the tools that would otherwise be run at build time for the same executables extracted from a native build.

Without this, there are multiple issues:
a) It will fail to start building since there are naming conflicts
between the "host" (build system) and "normal" (host system) object
files. This is resolved with a patch from buildroot.
b) It will then still fail to build since it will still try to build the
"host" objects, with a host compiler, but it will use the
configuration flags for the "target" OS. This is resolved by
importing the executables that would otherwise be run on the build
system from the intermediate stage of a native build, saved in a new
"dev" output. We also fake the "host" compiler as a tool which simply
touches its outputs.
c) Finally, there is a clang bug which causes a static assert that
something is trivially copyable to fire as a false positive. We
remove this check with a patch from rubyjs.

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
  • x86_64-freebsd (cross)
• 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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[aduh95]

For non-upstreamable patches, I think it makes more sense to vendor them in the repo rather than fetching them

[rhelmot]

I think it makes more sense for us to use another distro's patches if we're not super clear on the patch's long term situation because we can refer back to the other distro in order to see how they adjust the patch moving forward. If you think this is a silly/counterproductive/antisocial/etc argument I will gladly vendor it though!

[aduh95]

I haven't tested the cross compilation, but the change LGTM

[rhelmot]

An additional data point: I finally deployed a real application (immich) with node built cross for FreeBSD, and it works perfectly. There are some more patches coming in a separate PR for npm stuff, but it is definitely working without issue.