Require jruby to get JRuby.runtime

Author: headius

lib/ruby/stdlib/racc/parser.rb

@@ -188,6 +188,7 @@ class Parser
     Racc_Runtime_Core_Revision_R = %w$originalRevision: 1.8 $[1]
     begin
      if Object.const_defined?(:RUBY_ENGINE) and RUBY_ENGINE == 'jruby'
+       require 'jruby'
        require 'racc/cparse-jruby.jar'
        com.headius.racc.Cparse.new.load(JRuby.runtime, false)
      else