adapt to apfs.util flag diff in catalina/big sur
adapt to apfs.util flag diff in catalina/big sur

Fixes #3957. Just runs both forms to minimize moving parts.

rycee/nix,NixOS/nix,rycee/nix,NixOS/nix,rycee/nix,rycee/nix,rycee/nix,NixOS/nix,NixOS/nix,NixOS/nix