ocamlbuild: isStatic -> isMusl for the "pie" hardening check

[anmonteiro]

Motivation for this change

This aligns this check with the OCaml compiler's:

nixpkgs/pkgs/development/compilers/ocaml/generic.nix

Line 69 in 687ed90

hardeningDisable = lib.optional (lib.versionAtLeast version "4.09" && stdenv.hostPlatform.isMusl) "pie";

Things done

• 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 via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• 21.11 Release Notes (or backporting 21.05 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.

[r-burns]

Hey, I think the hardeningDisable here can be removed entirely after #135619 (currently in staging), care to give it a try?

I'm okay with merging this as an interim fix, as long as we don't forget to reenable PIE hardening after #135619 lands.

[anmonteiro]

I tried the staging branch without this fix and still couldn't compile ocamlbuild

[r-burns]

Hmm, could you specify what you tried?

Texinfo fails on staging due to #139470, but after checking out 445a245 and reverting 1165533 I was able to build pkgsMusl.ocamlPackages.ocamlbuild.

[anmonteiro]

I think I might not have selected the right revision earlier. This is indeed working in staging.