Refine fullscreen support

core/prelude-core.el

@@ -515,16 +515,16 @@ With numeric prefix arg DEC, decrement the integer by DEC amount."
   (prelude-increment-integer-at-point (- (or dec 1))))
 
 ;;; Emacs in OSX already has fullscreen support
-(when (eq window-system 'x)
-  (defun prelude-fullscreen ()
-    "Makes Emacs window fullscreen.
+;;; Emacs has a similar built-in command in 24.4
+(defun prelude-fullscreen ()
+  "Make Emacs window fullscreen.
 
 This follows freedesktop standards, should work in X servers."
   (interactive)
+  (if (eq window-system 'x)
       (x-send-client-message nil 0 nil "_NET_WM_STATE" 32
-                           '(2 "_NET_WM_STATE_FULLSCREEN" 0)))
-  (global-set-key (kbd "<f11>") 'prelude-fullscreen)
-)
+                             '(2 "_NET_WM_STATE_FULLSCREEN" 0))
+    (error "Only X server is supported")))
 
 (provide 'prelude-core)
 ;;; prelude-core.el ends here

core/prelude-global-keybindings.el

@@ -96,6 +96,9 @@
 ;; replace buffer-menu with ibuffer
 (global-set-key (kbd "C-x C-b") 'ibuffer)
 
+(unless (fboundp 'toggle-frame-fullscreen)
+  (global-set-key (kbd "<f11>") 'prelude-fullscreen))
+
 ;; toggle menu-bar visibility
 (global-set-key (kbd "<f12>") 'menu-bar-mode)