Ability to provide alternate timing implementation
diff --git a/include/polarssl/timing.h b/include/polarssl/timing.h
index 5ab000e..cb6abe3 100644
--- a/include/polarssl/timing.h
+++ b/include/polarssl/timing.h
@@ -3,7 +3,7 @@
  *
  * \brief Portable interface to the CPU cycle counter
  *
- *  Copyright (C) 2006-2013, Brainspark B.V.
+ *  Copyright (C) 2006-2014, Brainspark B.V.
  *
  *  This file is part of PolarSSL (http://www.polarssl.org)
  *  Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
@@ -27,6 +27,12 @@
 #ifndef POLARSSL_TIMING_H
 #define POLARSSL_TIMING_H
 
+#include "config.h"
+
+#if !defined(POLARSSL_TIMING_ALT)
+// Regular implementation
+//
+
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -72,4 +78,8 @@
 }
 #endif
 
+#else  /* POLARSSL_TIMING_ALT */
+#include "timing_alt.h"
+#endif /* POLARSSL_TIMING_ALT */
+
 #endif /* timing.h */