message: [VcpkgPaths.cpp] Don't modify and ref on the fly
diff: @@ -318,9 +318,9 @@ namespace vcpkg
  // VS2017
  Optional<Toolset> vs2017_toolset;
  - for (const fs::path& instance : vs2017_installation_instances)
  + for (const std::string& instance : vs2017_installation_instances)
  {
  - const fs::path vc_dir = instance / "VC";
  + const fs::path vc_dir = fs::path{instance} / "VC";
  // Skip any instances that do not have vcvarsall.
  const fs::path vcvarsall_dir = vc_dir / "Auxiliary" / "Build";
  