fix(parse): guard not to add empty arg

src/parse.c

@@ -32,7 +32,9 @@ void parse_worker(struct Args *args, char *arg_position,
     }
     return;
   } else if (isspace(line[0])) {
+    if (arg_length != 0) {
       add_arg(args, arg_position, arg_length);
+    }
     while (line[0] != '\n' && isspace(line[0])) {
       line++;
     }