    # File lib/phusion_passenger/utils.rb, line 1004
            def self.list_trappable
                    ruby_engine = defined?(RUBY_ENGINE) ? RUBY_ENGINE : "ruby"
                    case ruby_engine
                    when "ruby"
                            result = Signal.list
                            result.delete("ALRM")
                            result.delete("VTALRM")
                    when "jruby"
                            result = Signal.list
                            result.delete("QUIT")
                            result.delete("ILL")
                            result.delete("FPE")
                            result.delete("KILL")
                            result.delete("SEGV")
                            result.delete("USR1")
                    else
                            result = Signal.list
                    end

                    # Don't touch SIGCHLD no matter what! On OS X waitpid() will
                    # malfunction if SIGCHLD doesn't have a correct handler.
                    result.delete("CLD")
                    result.delete("CHLD")

                    # Other stuff that we don't want to trap no matter which
                    # Ruby engine.
                    result.delete("STOP")

                    return result
            end