haskell-modules: Pass -split-sections when cross-compiling

[wolfgangwalther]

This works around #286285 by passing --enable-split-sections instead of ghc-options.

This enables dead code elimination for pkgsCross and pkgsStatic, which did not work before.

Example: pkgsStatic.haskellPackages.cabal2nix

Before this change:

% du -h /nix/store/p9cl25mfl1l1gg5g9yvjfrqrrnywk9z0-cabal2nix-static-x86_64-unknown-linux-musl-2.19.1/bin/*
35M	/nix/store/p9cl25mfl1l1gg5g9yvjfrqrrnywk9z0-cabal2nix-static-x86_64-unknown-linux-musl-2.19.1/bin/cabal2nix
24M	/nix/store/p9cl25mfl1l1gg5g9yvjfrqrrnywk9z0-cabal2nix-static-x86_64-unknown-linux-musl-2.19.1/bin/hackage2nix

With this change:

% du -h /nix/store/q6nmkykk3im40lgvgy77njpr1d93gv7k-cabal2nix-static-x86_64-unknown-linux-musl-2.19.1/bin/*
15M	/nix/store/q6nmkykk3im40lgvgy77njpr1d93gv7k-cabal2nix-static-x86_64-unknown-linux-musl-2.19.1/bin/cabal2nix
9,5M	/nix/store/q6nmkykk3im40lgvgy77njpr1d93gv7k-cabal2nix-static-x86_64-unknown-linux-musl-2.19.1/bin/hackage2nix

Things done

• Built on platform(s)
  • x86_64-linux: pkgsStatic.haskellPackages.cabal2nix
  • 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/)
• 24.05 Release Notes (or backporting 23.05 and 23.11 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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[wolfgangwalther]

Will be merged in #286941.