I believe the issue is that you git cloned the main repo.
If I am not mistaken you would have to checkout the antminer branch, but I am not sure. I was not able to clone the correct part of the git. I suppose I could just download the branch and try to compile...
Exactly. You have to clone that repository and then checkout the feature/antminer-u1-support branch. If you don't see driver-antminer.c in the folder you are not going to get AntMiner U1 support by compiling.