This is basically the spiritual sucessor to Thirty-Two-Bit, my little dinky Linux distro based off of gray386linux, for, well, i386 computers. This is kinda like that but a zillion times better.
The base for this is Buildroot 2016.02, which was the last to support the Intel 386. I had to do a little work for it to work on modern computers, but it does!
Make sure you have all the normal dependancies for Buildroot installed, and then you should be pretty good to go. The only other dependancy is probably mtools so you have mcopy.
make 386root_defconfig # To copy the configuration files for 386root
make # Builds the distro (use -j flags!)
sudo board/386root/make_disk.sh # Makes the disk image (needs root)