```ruby
# ext/games_dice/extconf.rb
if RUBY_DESCRIPTION =~ /jruby/
  mfile = open("Makefile", "wb")
  mfile.puts '.PHONY: install'
  mfile.puts 'install:'
  mfile.puts "\t" + '@echo "Extensions not installed, falling back to pure Ruby version."'
  mfile.close
else
  require 'mkmf'
  create_makefile( 'games_dice/games_dice' )
end
```

Stop detecting Ruby types, and rely on mkmf to make the correct decision
user
```ruby
# ext/games_dice/extconf.rb
can_compile_extensions = false
want_extensions = true

begin
  require 'mkmf'
  can_compile_extensions = true
rescue Exception
  # This will appear only in verbose mode.
  $stderr.puts "Could not require 'mkmf'. Not fatal: The extensions are optional."
end


if can_compile_extensions && want_extensions
  create_makefile( 'games_dice/games_dice' )

else
  # Create a dummy Makefile, to satisfy Gem::Installer#install
  mfile = open("Makefile", "wb")
  mfile.puts '.PHONY: install'
  mfile.puts 'install:'
  mfile.puts "\t" + '@echo "Extensions not installed, falling back to pure Ruby version."'
  mfile.close

end
```
assistant