Fix #ifdef for GDK_SUPER_MASK.
diff --git a/src/gui_gtk_x11.c b/src/gui_gtk_x11.c
index 76ca4fe..e58ed73 100644
--- a/src/gui_gtk_x11.c
+++ b/src/gui_gtk_x11.c
@@ -889,7 +889,7 @@
 	modifiers |= MOD_MASK_CTRL;
     if (state & GDK_MOD1_MASK)
 	modifiers |= MOD_MASK_ALT;
-#ifdef GDK_SUPER_MASK
+#if GTK_CHECK_VERSION(2,10,0)
     if (state & GDK_SUPER_MASK)
 	modifiers |= MOD_MASK_META;
 #endif