Key wrapping API definition

Define the Key Wrapping API
diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index 17208b5..70820be 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -308,6 +308,7 @@
 //#define MBEDTLS_DHM_ALT
 //#define MBEDTLS_ECJPAKE_ALT
 //#define MBEDTLS_GCM_ALT
+//#define MBEDTLS_NIST_KW_ALT
 //#define MBEDTLS_MD2_ALT
 //#define MBEDTLS_MD4_ALT
 //#define MBEDTLS_MD5_ALT
@@ -2249,6 +2250,19 @@
 #define MBEDTLS_HMAC_DRBG_C
 
 /**
+ * \def MBEDTLS_NIST_KW_C
+ *
+ * Enable the Key Wrapping mode for 128-bit block ciphers,
+ * as defined in NIST SP 800-38F. Only KW and KWP modes
+ * are supported. At the moment, only AES is approved by NIST.
+ *
+ * Module:  library/nist_kw.c
+ *
+ * Requires: MBEDTLS_AES_C and MBEDTLS_CIPHER_C
+ */
+//#define MBEDTLS_NIST_KW_C
+
+/**
  * \def MBEDTLS_MD_C
  *
  * Enable the generic message digest layer.