I found that on a fresh minimal install of ubuntu (via DietPi) on a raspberry pi zero 2, that 'libc6-dev' was missing and preventing the overlayfs-tool from building (missing header file). Once I ran 'apt install libc6-dev' myself, the overlyfs-tools project then build cleanly and I was able to get it working. But the break in the build made a bit of a mess during the initial install of zram-config and left things in a weird state until I uninstalled it (which was also broken) and cleanly re-installed it.
I found that on a fresh minimal install of ubuntu (via DietPi) on a raspberry pi zero 2, that 'libc6-dev' was missing and preventing the overlayfs-tool from building (missing header file). Once I ran 'apt install libc6-dev' myself, the overlyfs-tools project then build cleanly and I was able to get it working. But the break in the build made a bit of a mess during the initial install of zram-config and left things in a weird state until I uninstalled it (which was also broken) and cleanly re-installed it.