File db-4.8.30-cwd-db_config.patch of Package libdb4

--- db-5.3.28/src/env/env_open.c.old	2017-06-26 10:32:11.011419981 +0200
+++ db-5.3.28/src/env/env_open.c	2017-06-26 10:32:46.893721233 +0200
@@ -473,7 +473,7 @@
 	env->db_mode = mode == 0 ? DB_MODE_660 : mode;
 
 	/* Read the DB_CONFIG file. */
-	if ((ret = __env_read_db_config(env)) != 0)
+	if (env->db_home != NULL && (ret = __env_read_db_config(env)) != 0)
 		return (ret);
 
 	/*