If you're following the instructions to build your own 8BitRobots distribution, you may find the compilation fails with errors like the following:

undefined reference to `__atomic_fetch_add_8'

While I'm not entirely sure why this happen, a fix is described here https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=874531

The easiest way to apply this it to locate the various Makefile where the build fails, find the LIBS= directive in each one, and add -latomic to it.

LIBS = -latomic

 Restart and the compilation should move on.