message: Fix logic for determining prefer-dynamic for a dylib.
diff: @@ -792,7 +792,7 @@ fn build_base_args(
  }
  let prefer_dynamic = (unit.target.for_host() && !unit.target.is_custom_build())
  - || (crate_types.contains(&CrateType::Dylib) && bcx.ws.members().any(|p| *p != unit.pkg));
  + || (crate_types.contains(&CrateType::Dylib) && !cx.is_primary_package(unit));
  if prefer_dynamic {
  cmd.arg("-C").arg("prefer-dynamic");
  }
  