def find_builder_for(target, source, features)
      @builders.values.find do |builder|
        features_met?(builder, features) and builder.produces?(target, source, self)
      end
    end
def find_builder_for(target, source, features)
      @builders.values.find do |builder|
        features_met?(builder, features) and builder.produces?(target, source, self)
      end
    end
Find a builder that meets the requested features and produces a target
 of the requested name.

 @param target [String]
   Target file name.
 @param source [String]
   Source file name.
 @param features [Array<String>]
   See {#register_builds}.

 @return [Builder, nil]
   The builder found, if any.