* cris/cris-sim.h (enum cris_unknown_syscall_action_type)

	* cris/cris-sim.h (enum cris_unknown_syscall_action_type)
	(cris_unknown_syscall_action): Declare.
	* cris/sim-if.c (cris_unknown_syscall_action): Define.
	(cris_options): Add cris-unknown-syscall option.
	(cris_option_handler): Correct comment about and error message for
	invalid --cris-cycles argument.  Handle --cris-unknown-syscall.
	* cris/traps.c: Include stdarg.h
	(cris_unknown_syscall): New function.
	(cris_break_13_handler): Instead of sim_io_eprintf and
	sim_engine_halt, call cris_unknown_syscall to handle more or less
	unknown syscalls.  Adjust code as necessary to handle return
	value.