check_window_system 1247 src/fontset.c    check_window_system (NULL);
check_window_system 1882 src/fontset.c    check_window_system (NULL);
check_window_system  127 src/frame.c      check_window_system (f);
check_window_system 5325 src/frame.c      check_window_system (NULL);
check_window_system 1358 src/frame.h    extern WINDOW_SYSTEM_RETURN void check_window_system (struct frame *);
check_window_system 1622 src/haikufns.c   check_window_system (f);
check_window_system  313 src/haikumenu.c   check_window_system (f);
check_window_system 4125 src/haikuterm.c   check_window_system (f);
check_window_system 2001 src/pgtkfns.c    check_window_system (NULL);
check_window_system 2288 src/pgtkfns.c    check_window_system (NULL);
check_window_system 3723 src/pgtkfns.c    check_window_system (f);
check_window_system 1059 src/pgtkmenu.c   check_window_system (f);
check_window_system  460 src/pgtkterm.c   check_window_system (f);
check_window_system  563 src/pgtkterm.c   check_window_system (f);
check_window_system  108 src/w32menu.c    check_window_system (f);
check_window_system 1632 src/xfaces.c     check_window_system (NULL);
check_window_system 9132 src/xfns.c       check_window_system (f);
check_window_system 9353 src/xfns.c       check_window_system (f);
check_window_system 2431 src/xmenu.c      check_window_system (f);
check_window_system 2455 src/xselect.c    check_window_system (decode_live_frame (frame));