There are instructions for configuring KallisitiOS on the website, but they are focused on installing globally in /opt/ whereas I'm going to explain how to setup KOS in your home folder.
Step 1. Clone all the things
Firstly you need to get the code. KOS and its counterpart library port repository both use GIT. So, let's make a directory called "Dreamcast" and clone those things:
git clone git://git.code.sf.net/p/cadcdev/kallistios
git clone --recursive git://git.code.sf.net/p/cadcdev/kos-ports
At this point you'll have two folders, kallistios and kos-ports. Forget about kos-ports for the time being.
Step 2. Building the toolchain
The "toolchain" is the GCC cross-compiler you need to build for the Dreamcast. There are two architectures to build: sh-elf and arm-eabi.
KOS has some scripts for helping you to build the toolchain, and these are found in the "utils/dc-chain" folder.
The first thing we need to do is alter the installation location to our "~/Dreamcast" folder.
Open "utils/dc-chain/Makefile" in a text editor, near the top of the file you'll find the following lines:
sh_prefix := /opt/toolchains/dc/$(sh_target)
arm_prefix := /opt/toolchains/dc/$(arm_target)
You'll need to change them to:
sh_prefix := /home/YOUR_USERNAME/Dreamcast/toolchain/$(sh_target)
arm_prefix := /home/YOUR_USERNAME/Dreamcast/toolchain/$(arm_target)
Now, we need to make sure we have all the required dependencies, run this command first:
sudo dnf builddep gcc
Once that's done, run the following commands:
You'll have to wait for each step to complete in full. Watch for any errors during the build, you may having additional missing dependencies. Hit up Google if that's the case :)
Step 3. Building KOS
OK, at this point you should have a "~/Dreamcast/toolchain" folder with stuff in it. You now need to set up your environment. Run the following commands:
cp docs/environ.sh.sample environ.sh
Now open "~/Dreamcast/kallistios/environ.sh" in a text editor and change the KOS_BASE export so it's something like this:
Also change any references to sh-elf or arm-eabi to point to the folders in "~/Dreamcast/toolchain".
Edit your ~/.bashrc file and add the following to the end of it:
Now, open a new terminal, run the following:
Step 4. Build the ports you need
From now on it's up to you, you can "cd" into the individual ports that you want and run:
make install clean
Everything is now ready to go!