Change "_Quit-without-saving" in the Game dropdown menu to be
"\177Quit-without-saving". That makes the prefix used on OSX to
prevent matching "^[&]?[Qq][Uu][Ii][Tt].*" be invisible.
Also change the order of the choices for the command+Q and
application dropdown menu entry "quit nethack" so that "cancel
and return to game" is the default for arbitrary response to the
confirmation prompt. <return> and <space> select "quit without
saving". Note that the nethack dropdown menu is OSX-specific
(a Qt feature to emulate other OSX applications) and its
nethack->Quit action is separate-from/in-addition-to Game->Quit
menu action mentioned above (which runs nethack's #quit command).