* agent/gpg-agent.c (CHECK_PROBLEMS_INTERVAL): New.
(socket_takeover_detected): Remove.
(problem_detected): New.
(handle_tick): Don't check parent PID and homedir in this function.
(handle_connections): Spawn check_others_thread when needed.  Handle
AGENT_PROBLEM_PARENT_HAS_GONE and AGENT_PROBLEM_HOMEDIR_REMOVED.
(check_own_socket_thread): Check SHUTDOWN_PENDING variable in the
loop.  Use PROBLEM_DETECTED variable.
(check_others_thread): New.