Fix inconsistent #include style

Signed-off-by: Pekka Paalanen <ppaalanen@gmail.com>
diff --git a/clients/window.c b/clients/window.c
index ffa01d4..db48a39 100644
--- a/clients/window.c
+++ b/clients/window.c
@@ -51,7 +51,7 @@
 
 #include <linux/input.h>
 #include "wayland-util.h"
-#include "wayland-client.h"
+#include <wayland-client.h>
 #include "cairo-util.h"
 
 #include "window.h"