diff --git a/library/sha4.c b/library/sha4.c
index 383b4d2..466420a 100644
--- a/library/sha4.c
+++ b/library/sha4.c
@@ -1,7 +1,7 @@
 /*
  *  FIPS-180-2 compliant SHA-384/512 implementation
  *
- *  Copyright (C) 2006-2010, Brainspark B.V.
+ *  Copyright (C) 2006-2013, Brainspark B.V.
  *
  *  This file is part of PolarSSL (http://www.polarssl.org)
  *  Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
@@ -38,6 +38,8 @@
 #include <stdio.h>
 #endif
 
+#if !defined(POLARSSL_SHA4_ALT)
+
 /*
  * 64-bit integer manipulation macros (big endian)
  */
@@ -308,6 +310,8 @@
     }
 }
 
+#endif /* !POLARSSL_SHA4_ALT */
+
 /*
  * output = SHA-512( input buffer )
  */