cleanup library and some basic tests. Includes, add guards to includes
diff --git a/include/polarssl/pkcs12.h b/include/polarssl/pkcs12.h
index 4a13102..0920cd1 100644
--- a/include/polarssl/pkcs12.h
+++ b/include/polarssl/pkcs12.h
@@ -24,12 +24,12 @@
#ifndef POLARSSL_PKCS12_H
#define POLARSSL_PKCS12_H
-#include <string.h>
-
#include "md.h"
#include "cipher.h"
#include "asn1.h"
+#include <stddef.h>
+
#define POLARSSL_ERR_PKCS12_BAD_INPUT_DATA -0x1F80 /**< Bad input parameters to function. */
#define POLARSSL_ERR_PKCS12_FEATURE_UNAVAILABLE -0x1F00 /**< Feature not available, e.g. unsupported encryption scheme. */
#define POLARSSL_ERR_PKCS12_PBE_INVALID_FORMAT -0x1E80 /**< PBE ASN.1 data not as expected. */