Dear JLP,
Thank you for your answer, but it seems, this repository does not contain the drivers' sources. It contains the sources of XRT utilities, and we've successfully built them even before we've asked this question.
Our problem is that we cannot use the drivers compiled and tested on RehHat 8.4 (for instance) when we work on RedHat 8.7. The drivers should be compiled with the installed Linux kernel, because they are very sensitive to the kernel version.
Maybe there is another public GitHub repository containing the XRT drivers' sources (not XRT utilities)?