erlang: cross compile support

[illegalprime]

Motivation for this change

Adds support to cross compile the erlang interpreter, patchShebangs is still broken for other architectures but it still works on the physical board. (#33956)

Things done

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nox --run "nox-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Assured whether relevant documentation is up to date
• Fits CONTRIBUTING.md.

---

[Mic92]

Does the buildPackages prefix here actually makes a difference?
I only know that sometimes overrides in all-packages.nix breaks splicing
of the correct architecture. The problem when using this approach is
that it is no longer possible to override packages externally.

[illegalprime]

yea you're right, not sure, let me try it without those

[illegalprime]

@Mic92 just tried it and it doesn't work if I don't explicitly set buildPackages, maybe i'm going about this wrong but it seems to not be able to find perl if I remove buildPackages.

[Ericson2314]

What is the error?

[illegalprime]

sorry, I was building it with wxSupport, which doesn't work right now, this patch is to cross-compile erlang without wxSupport (GUI stuff). after fiddling the smallest I can get it is:

{
  nativeBuildInputs = [
    autoreconfHook
    makeWrapper
    perl
    gnum4
    buildPackages.libxslt
    libxml2
  ];
}

if I remove that buildPackages from libxslt I get a format error for xsltproc:

xsltproc --output "../man3/array.3" --stringparam company "Ericsson AB" --stringparam docgen "/build/source/bootstrap/lib/erl_docgen" --stringparam gendate "$date" --stringparam appname "stdlib" --stringparam appver "3.4.5" --stringparam specs_file "$specs_file" --xinclude -path /build/source/bootstrap/lib/erl_docgen/priv/dtd  -path /build/source/bootstrap/lib/erl_docgen/priv/dtd_man_entities /build/source/bootstrap/lib/erl_docgen/priv/xsl/db_man.xsl array.xml
/nix/store/cinw572b38aln37glr0zb8lxwrgaffl4-bash-4.4-p23/bin/bash: line 2: /nix/store/rlv5jd00hksp449aqizf33q8nnrx6j80-libxslt-1.1.33-armv7l-unknown-linux-gnueabihf-bin/bin/xsltproc: cannot execute binary file: Exec format error
make[5]: *** [/build/source/make/armv7l-unknown-linux-gnueabihf/otp.mk:293: ../man3/array.3] Error 126
make[5]: Leaving directory '/build/source/lib/stdlib/doc/src'
make[4]: *** [/build/source/make/otp_release_targets.mk:182: release_docs] Error 2
make[4]: Leaving directory '/build/source/lib/stdlib/doc/src'
make[3]: *** [/build/source/make/otp_subdir.mk:29: release_docs] Error 2
make[3]: Leaving directory '/build/source/lib/stdlib'
make[2]: *** [/build/source/make/otp_subdir.mk:29: release_docs] Error 2
make[2]: Leaving directory '/build/source/lib'
make[1]: *** [Makefile:416: release_docs] Error 2
make[1]: Leaving directory '/build/source'
make: *** [Makefile:1029: install-docs] Error 2

[Ericson2314]

Thanks for investigating! We should definitely get to the bottom of why libxslt is different.

[Ericson2314]

Opened #58327 in case that makes a difference.

I only know that sometimes overrides in all-packages.nix breaks splicing
of the correct architecture.

This PR works around that.

[Ericson2314]

That other PR causes more problems. (I almost rather remove the with pkgs!) Can we do everything but xslt leaving a TODO?

[cw789]

Can we do everything but xslt leaving a TODO?

Am I right if I think it then will work already with erlang_nox?

[cw789]

Is there anything I could help in bringing this forward?
I think Nix could be "The Tool" for building cross compiled Elixir / Erlang releases.

[FRidh]

Please rebase. This PR looks good to me.

[Ericson2314]

Per https://github.com/NixOS/nixpkgs/pull/58042/files#r292261100 we should get rid of most of the buildPackges. in the nativeBuildInputs list except for the weird misbehaving XSLT, and leave a TODO for it.

[stale]

Thank you for your contributions.
This has been automatically marked as stale because it has had no activity for 180 days.
If this is still important to you, we ask that you leave a comment below. Your comment can be as simple as "still important to me". This lets people see that at least one person still cares about this. Someone will have to do this at most twice a year if there is no other activity.
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[tolbrino]

👍 to move this forward.

[stale]

I marked this as stale due to inactivity. → More info

[domenkozar]

#100835 is still outdated, but slightly newer.