Makefile improvements

[HectorPeeters]

When i was trying to build your project i encountered a few issues on my machine.

• The first time I ran make qemu I got the following error: make: ./misc/gen-grub-config.sh: Command not found This was quickly solved by changing that line to: bash ./misc/gen-grub-config.sh

• But then the project build succeeded but it did not output a SnowflakeOS.iso. After installing xorriso it worked perfectly fine! This might be nice to add to the README.md for other people who experience the same problem.

Overall a very nice project!

[29jm]

Thanks for the report and kind words, I'll fix it asap! The whole readme needs some love for sure :)

[29jm]

Done!