Make --standalone play nice with --local

I'm not sure if using relative paths in the generated script is best for
this case, since it makes the script not movable, but that can be
improved later.

bundler/lib/bundler/cli/install.rb

@@ -148,7 +148,7 @@ def normalize_settings
       Bundler.settings.set_command_option :path, nil if options[:system]
       Bundler.settings.set_command_option_if_given :path, options[:path]
 
-      if options["standalone"] && Bundler.settings[:path].nil?
+      if options["standalone"] && Bundler.settings[:path].nil? && !options["local"]
         Bundler.settings.temporary(:path_relative_to_cwd => false) do
           Bundler.settings.set_command_option :path, "bundle"
         end

bundler/lib/bundler/installer/standalone.rb

@@ -47,7 +47,7 @@ def extensions_dir
     end
 
     def bundler_path
-      Bundler.root.join(Bundler.settings[:path], "bundler")
+      Bundler.root.join(Bundler.settings[:path].to_s, "bundler")
     end
 
     def gem_path(path, spec)

bundler/spec/install/gems/standalone_spec.rb

@@ -461,3 +461,31 @@
 
   include_examples("bundle install --standalone")
 end
+
+RSpec.describe "bundle install --standalone --local" do
+  before do
+    gemfile <<-G
+      source "#{file_uri_for(gem_repo1)}"
+      gem "rack"
+    G
+
+    system_gems "rack-1.0.0", :path => default_bundle_path
+  end
+
+  it "generates script pointing to system gems" do
+    bundle "install --standalone --local --verbose"
+
+    expect(out).to include("Using rack 1.0.0")
+
+    load_error_ruby <<-RUBY, "spec"
+      require "./bundler/setup"
+
+      require "rack"
+      puts RACK
+      require "spec"
+    RUBY
+
+    expect(out).to eq("1.0.0")
+    expect(err).to eq("ZOMG LOAD ERROR")
+  end
+end