* xmenu.c (popup_get_selection): Pop down on C-g.

* xmenu.c (popup_get_selection): Pop down on C-g.
(set_frame_menubar): Install translations for Lucid/Motif/Lesstif that
pops down menu on C-g.
(xdialog_show): If dialog popped down and no button in the dialog was
pushed, call Fsignal to quit.
(xmenu_show): In no toolkit version, if menu returns NO_SELECT call
Fsignal to quit.

* xfns.c (Fx_file_dialog): Motif/Lesstif version:  Pop down on C-g.

* gtkutil.c (xg_initialize): Install bindings for C-g so that
dialogs and menus pop down.