lib/systems: use qemu-user package instead of custom definition

      let

        selectEmulator = pkgs:

          let

            qemu-user = pkgs.qemu.override {

              smartcardSupport = false;

              spiceSupport = false;

              openGLSupport = false;

              virglSupport = false;

              vncSupport = false;

              gtkSupport = false;

              sdlSupport = false;

              alsaSupport = false;

              pulseSupport = false;

              pipewireSupport = false;

              jackSupport = false;

              smbdSupport = false;

              seccompSupport = false;

              tpmSupport = false;

              capstoneSupport = false;

              enableDocs = false;

              hostCpuTargets = [ "${final.qemuArch}-linux-user" ];

            };

            wine = (pkgs.winePackagesFor "wine${toString final.parsed.cpu.bits}").minimal;

          in

          # Note: we guarantee that the return value is either `null` or a path

          else if final.isWindows

          then "${wine}/bin/wine${optionalString (final.parsed.cpu.bits == 64) "64"}"

          else if final.isLinux && pkgs.stdenv.hostPlatform.isLinux && final.qemuArch != null

          then "${qemu-user}/bin/qemu-${final.qemuArch}"

          then "${pkgs.qemu-user}/bin/qemu-${final.qemuArch}"

          else if final.isWasi

          then "${pkgs.wasmtime}/bin/wasmtime"

          else if final.isMmix