class Gem::Commands::BuildCommand

def build_package(gemspec)
  spec = Gem::Specification.load(gemspec)
  if spec
    Gem::Package.build(
      spec,
      options[:force],
      options[:strict],
      options[:output]
    )
  else
    alert_error "Error loading gemspec. Aborting."
    terminate_interaction 1
  end
end