Threading abstraction layer added
diff --git a/include/polarssl/threading.h b/include/polarssl/threading.h
new file mode 100644
index 0000000..4afaeea
--- /dev/null
+++ b/include/polarssl/threading.h
@@ -0,0 +1,84 @@
+/**
+ * \file threading.h
+ *
+ * \brief Threading abstraction layer
+ *
+ * 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>
+ *
+ * All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+#ifndef POLARSSL_THREADING_H
+#define POLARSSL_THREADING_H
+
+#include "config.h"
+
+#include <stdlib.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#define POLARSSL_ERR_THREADING_FEATURE_UNAVAILABLE -0x001A /**< The selected feature is not available. */
+#define POLARSSL_ERR_THREADING_BAD_INPUT_DATA -0x001C /**< Bad input parameters to function. */
+#define POLARSSL_ERR_THREADING_MUTEX_ERROR -0x001E /**< Locking / unlocking / free failed with error code. */
+
+#if defined(POLARSSL_THREADING_DUMMY)
+typedef void threading_mutex_t;
+#endif
+
+#if defined(POLARSSL_THREADING_PTHREAD)
+#include <pthread.h>
+typedef pthread_mutex_t threading_mutex_t;
+#endif
+
+#if defined(POLARSSL_THREADING_ALT)
+/* You should define the threading_mutex_t type in your header */
+#include "threading_alt.h"
+
+/**
+ * \brief Set your alternate threading implementation function
+ * pointers
+ *
+ * \param mutex_init the malloc function implementation
+ * \param mutex_free the free function implementation
+ * \param mutex_lock the lock function implementation
+ * \param mutex_unlock the unlock function implementation
+ *
+ * \return 0 if successful
+ */
+int threading_set_alt( int (*mutex_init)( threading_mutex_t * ),
+ int (*mutex_free)( threading_mutex_t * ),
+ int (*mutex_lock)( threading_mutex_t * ),
+ int (*mutex_unlock)( threading_mutex_t * ) );
+#endif /* POLARSSL_THREADING_ALT_C */
+
+/*
+ * The function pointers for mutex_init, mutex_free, mutex_ and mutex_unlock
+ */
+extern int (*polarssl_mutex_init)( threading_mutex_t *mutex );
+extern int (*polarssl_mutex_free)( threading_mutex_t *mutex );
+extern int (*polarssl_mutex_lock)( threading_mutex_t *mutex );
+extern int (*polarssl_mutex_unlock)( threading_mutex_t *mutex );
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* threading.h */