fix APPLICATION build errors

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@30601 a1c6a512-1295-4272-9138-f99709370657

apps/gui/skin_engine/skin_engine.c

@@ -45,6 +45,7 @@ static bool skins_initialising = true;
 /* App uses the host malloc to manage the buffer */
 #ifdef APPLICATION
 #define skin_buffer NULL
+#define skin_buffer_size 0
 void theme_init_buffer(void)
 {
     skins_initialising = false;