I have a Rakefile that includes this:

Jeweler::Tasks.new do |gem|
  # ...
  gem.add_dependency('json')
end

The gemspec that this generates builds a gem that can't be installed on jruby because the 'json' gem is native.

For jruby, this would have to be:

Jeweler::Tasks.new do |gem|
  # ...
  gem.add_dependency('json-jruby')
end

How do I conditionally add the dependency for 'json-jruby' when RUBY_ENGINE == 'java'?

It seems like my only option is to manually edit the gemspec file that jeweler generates to add the RUBY_ENGINE check. But I'd rather avoid this, since it kind of defeats the purpose of using jeweler in the first place.

Any ideas?