Compile without GPU

[XiangyPeng]

Hi, thank you for the great work.

Is that possible to compile "OpenPCDet" without GPU？ Our GPU will automatically cut down the script if the utilization rate of the GPU is lower than 5% for 5min. But the compile process takes longer than 5min. Therefore, I would like to know if it is possible to compile the "setup.py" without GPU.

Thank you in advance!