message: `export`: Only suggest installation of unbuilt packages
diff: @@ -87,7 +87,15 @@ namespace vcpkg::Commands::Export
  if (it != group_by_plan_type.cend() && !it->second.empty())
  {
  System::println(System::Color::error, "There are packages that have not been built.");
  - auto s = Strings::join(" ", specs, [](const PackageSpec& spec) { return spec.to_string(); });
  +
  + // No need to show all of them, just the user-requested ones. Dependency resolution will handle the rest.
  + std::vector<const ExportPlanAction*> unbuilt = it->second;
  + Util::erase_remove_if(unbuilt, [](const ExportPlanAction* a)
  + {
  + return a->request_type != RequestType::USER_REQUESTED;
  + });
  +
  + auto s = Strings::join(" ", unbuilt, [](const ExportPlanAction* a) { return a->spec.to_string(); });
  System::println("To build them, run:\n"
  " vcpkg install %s", s);
  Checks::exit_fail(VCPKG_LINE_INFO);
  