Use thread save settings alloc_str function where appropriate

src/libcharon/plugins/tnc_imc/tnc_imc_manager.c

@@ -43,6 +43,11 @@ struct private_tnc_imc_manager_t {
 	 * Next IMC ID to be assigned
 	 */
 	TNC_IMCID next_imc_id;
+
+	/**
+	 * Preferred language
+	 */
+	char *preferred_language;
 };
 
 METHOD(imc_manager_t, add, bool,
@@ -95,8 +100,7 @@ METHOD(imc_manager_t, remove_, imc_t*,
 METHOD(imc_manager_t, get_preferred_language, char*,
 	private_tnc_imc_manager_t *this)
 {
-	return lib->settings->get_str(lib->settings,
-					"charon.plugins.tnc-imc.preferred_language", "en");
+	return this->preferred_language;
 }
 
 METHOD(imc_manager_t, notify_connection_change, void,
@@ -208,6 +212,7 @@ METHOD(imc_manager_t, destroy, void,
 		imc->destroy(imc);
 	}
 	this->imcs->destroy(this->imcs);
+	free(this->preferred_language);
 	free(this);
 }
 
@@ -232,6 +237,8 @@ imc_manager_t* tnc_imc_manager_create(void)
 		},
 		.imcs = linked_list_create(),
 		.next_imc_id = 1,
+		.preferred_language = lib->settings->alloc_str(lib->settings,
+					"charon.plugins.tnc-imc.preferred_language", "en");
 	);
 
 	return &this->public;