Clang-13 error
**clang-13 shows warning**
During executing "make" too many errors emitted
![20220320_160508](https://user-images.githubusercontent.com/101918064/159153985-8ac3d8f4-f78c-4f4b-9d1e-c4731365ba08.jpg)
![20220320_160522](https://user-images.githubusercontent.com/101918064/159153987-b8b83865-e686-4308-ab22-4976a2d0fd2a.jpg)
![20220320_160555](https://user-images.githubusercontent.com/101918064/159153991-9e6e0096-92aa-4485-a756-e180627dfa01.jpg)

