* diagnostics.h, diagnostics.c (print_sigint_message): New function.

	* diagnostics.h, diagnostics.c (print_sigint_message): New function.
	* linux-target.c (linux_process_rcmd): Add monitor commands
	"interrupt-with-SIGSTOP and interrupt-with-SIGINT".
	* server.h (struct child_process): Add new field
	interrupt_with_SIGSTOP.
	* thread-db.c (thread_db_break_program): Interrupt using either
	SIGSTOP or SIGINT depending upon user's preference.