vamp-plugin-sdk: disable parallelism to avoid build failures

[uninsane]

Description of changes

• upstream issue: make -j fails on high core count machine vamp-plugins/vamp-plugin-sdk#12
• before this patch, i tried building this 4 times on a 24 core machine (.#pkgsCross.aarch64-multiplatform.vamp-plugin-sdk), and all 4 builds failed. signatures like:
  • aarch64-unknown-linux-gnu-ld: error: ./libvamp-hostsdk.a: file too short
  • aarch64-unknown-linux-gnu-ld: ./libvamp-hostsdk.a: error adding symbols: no more archived files
• with this patch, it builds first try.

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, 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/)
• 23.11 Release Notes (or backporting 23.05 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.

[Artturin]

Updated the issue link