openssl: OpenSSL 1.1.0 is thread-safe so we don't have to setup callbacks

src/libstrongswan/plugins/openssl/openssl_plugin.c

@@ -65,6 +65,11 @@ struct private_openssl_plugin_t {
 	openssl_plugin_t public;
 };
 
+/**
+ * OpenSSL is thread-safe since 1.1.0
+ */
+#if OPENSSL_VERSION_NUMBER < 0x10100000L
+
 /**
  * Array of static mutexs, with CRYPTO_num_locks() mutex
  */
@@ -227,6 +232,14 @@ static void threading_cleanup()
 	cleanup->destroy(cleanup);
 }
 
+#else /* OPENSSL_VERSION_NUMBER */
+
+#define threading_init()
+
+#define threading_cleanup()
+
+#endif
+
 /**
  * Seed the OpenSSL RNG, if required
  */