openssl: Simplify wrapping private key objects

src/libstrongswan/plugins/openssl/openssl_util.h

@@ -57,6 +57,15 @@ bool openssl_compute_shared_key(EVP_PKEY *priv, EVP_PKEY *pub, chunk_t *shared);
  */
 bool openssl_fingerprint(EVP_PKEY *key, cred_encoding_type_t type, chunk_t *fp);
 
+/**
+ * Wrap the given OpenSSL private key in a type-specific private key object.
+ *
+ * @param key		key object to wrap
+ * @param engine	TRUE if key can't be accessed directly
+ * @returns			created object or NULL if key type is not supported
+ */
+private_key_t *openssl_wrap_private_key(EVP_PKEY *key, bool engine);
+
 /**
  * Concatenates two bignums into a chunk, thereby enforcing the length of
  * a single BIGNUM, if necessary, by prepending it with zeros.