Add no-op rubocop for rbx

Author: bf4

Rakefile

@@ -6,10 +6,19 @@ begin
 rescue LoadError
 else
   Rake::Task[:rubocop].clear if Rake::Task.task_defined?(:rubocop)
-  desc 'Execute rubocop'
-  RuboCop::RakeTask.new(:rubocop) do |task|
-    task.options = ['--rails', '--display-cop-names', '--display-style-guide']
-    task.fail_on_error = true
+  if !defined?(::Rubinius)
+    Rake::Task[:rubocop].clear if Rake::Task.task_defined?(:rubocop)
+    desc 'Execute rubocop'
+    RuboCop::RakeTask.new(:rubocop) do |task|
+      task.options = ['--rails', '--display-cop-names', '--display-style-guide']
+      task.fail_on_error = true
+    end
+  else
+    desc 'No-op rubocop to avoid rbx segfault'
+    task :rubocop do
+      puts 'Skipping rubocop on rbx due to segfault'
+      puts 'https://github.com/rubinius/rubinius/issues/3499'
+    end
   end
 end