[mutter] keybindings: Do not depend on linux headers for above-tab key

[Florian Müllner <fmuellner src gnome org>]

commit 565b9d73d532c7759fce432eb5c397ff535ac0ff
Author: Florian Müllner <fmuellner gnome org>
Date:   Mon Sep 22 15:06:22 2014 +0200

    keybindings: Do not depend on linux headers for above-tab key
    
    Commit 2f229c3928be3a removed the code to compute the above-tab
    keycode and replaced it with a simple constant from linux/input.h.
    We obviously cannot depend on linux headers on non-linux systems,
    so provide a fallback definition in that case (which is expected
    to work assuming the system is using the Xorg xf86-input-keyboard
    driver).
    
    https://bugzilla.gnome.org/show_bug.cgi?id=737135

 src/core/keybindings.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/src/core/keybindings.c b/src/core/keybindings.c
index 1566460..e1c909b 100644
--- a/src/core/keybindings.c
+++ b/src/core/keybindings.c
@@ -40,7 +40,11 @@
 #include <meta/prefs.h>
 #include "meta-accel-parse.h"
 
+#ifdef __linux__
 #include <linux/input.h>
+#elif !defined KEY_GRAVE
+#define KEY_GRAVE 0x29 /* assume the use of xf86-input-keyboard */
+#endif
 
 #include "backends/x11/meta-backend-x11.h"
 #include "x11/window-x11.h"