* linux-nat.c (resume_callback): Add more debugging output.

	* linux-nat.c (resume_callback): Add more debugging output.
	(linux_nat_has_pending_sigint): New function, based on
	linux_nat_has_pending.
	(set_ignore_sigint, maybe_clear_ignore_sigint): New functions.
	(stop_wait_callback): Remove flush_mask handling.  Honor
	ignore_sigint.  Call maybe_clear_ignore_sigint.  Pass NULL
	to recursive calls.
	(linux_nat_has_pending, flush_callback): Remove.
	(linux_nat_filter_event): Check for ignore_sigint.
	(linux_nat_wait): Remove flush_mask support and call to
	flush_callback.  Use set_ignore_sigint and maybe_clear_ignore_sigint.
	* linux-nat.h (struct lwp_info): Add ignore_sigint field.

	* gdb.threads/manythreads.exp: Use remote_expect instead of after.
	Add a test for duplicated SIGINTs.