- First replacement of xyssl by polarssl where needed

diff --git a/include/polarssl/arc4.h b/include/polarssl/arc4.h
index f30743b..9c20a9e 100644
--- a/include/polarssl/arc4.h
+++ b/include/polarssl/arc4.h
@@ -1,8 +1,8 @@
 /**
  * \file arc4.h
  */
-#ifndef XYSSL_ARC4_H
-#define XYSSL_ARC4_H
+#ifndef POLARSSL_ARC4_H
+#define POLARSSL_ARC4_H
 
 /**
  * \brief          ARC4 context structure