* nsmenu.m (pop_down_menu): New function.

* nsmenu.m (pop_down_menu): New function.
(ns_popup_dialog): Call it on unwind.
(EmacsDialogPanel-runDialogAt:): Check popup_activated_flag and
call timer_check() (Bug#2154).
(EmacsMenu-menuNeedsUpdate:): Don't call ns_update_menu if
handling_signal is set.
(EmacsMenu-fillWithWidgetValue:): Set submenu title.

* s/darwin.h: Same and NO_SOCK_SIGIO as well.

* nsterm.m (ns_read_socket): Same and don't set handling_signal.

* keyboard.c (poll_for_input_1, handle_async_input): Set
handling_signal under HAVE_NS.