Errors when using on ubuntu

HI dear author,  
     Honor to write a letter here, I have met some mistakes when using wolf3d, do you know why? 

![image](https://user-images.githubusercontent.com/51076736/113106643-95dad280-9235-11eb-92ff-2c6e3b44c00f.png)  


thank you  
best regards  
William
