Bumping the MacOS target version to 10.12 signalled xcbuild that libcompression is available on Darwin, but libcompression is not OSS (even though an LZFSE reference implementation is), and it is not part of a framework for us to make impure, so this patch disables it.

I can't think of a way to get these deps otherwise: compression.h is at /Library/Developer/CommandLineTools/SDKs/MacOSX.sdk/usr/include/compression.h and libcompression.dylib is at /usr/lib/libcompression.dylib

Motivation for this change

Make it build again.

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 nix-review --run "nix-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)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.

Notify maintainers

cc @copumpkin @matthewbauer