gdb/

gdb/
	Support a ring of related breakpoints.
	* breakpoint.c (watchpoint_del_at_next_stop): New, move here code from
	other functions, add gdb_assert.
	(update_watchpoint, watchpoint_check): Add gdb_assert.  Use
	watchpoint_del_at_next_stop.
	(bpstat_check_watchpoint): Use watchpoint_del_at_next_stop.
	(bpstat_stop_status): Handle ring in related_breakpoint.
	(set_raw_breakpoint_without_location): Initialize ring in
	related_breakpoint.
	(delete_breakpoint): Handle ring in related_breakpoint, use
	watchpoint_del_at_next_stop.
	(map_breakpoint_numbers): Handle ring in related_breakpoint.

gdb/testsuite/
	Support a ring of related breakpoints.
	* gdb.base/watchpoint-delete.c: New file.
	* gdb.base/watchpoint-delete.exp: New file.