This OS is a complete Mess. (Not now but will)
You need i686 cross-compilers to build. Here
The compilers are expected to be in $HOME/opt/cross/bin/
You need GRUB utilities and xorriso to execute grub-mkrescue.
You need qemu-system-i386 to test.
make # This will generate messos.iso file
make run # This will run MessOS with QEMU
make clean # This will make files cleaner than your room