Extract the files from the deb package (ex: dpkg -x file.debnew-folder)
Copy the SDL2-Image or SDL2-Mixer folder (located in the cmake folder of the extracted deb) to /usr/lib/architecture**/cmake folder on your PC.
Note that my architecture folder is x86_64-linux-gnu, yours may differ.
Run make.sh in the cdogs directory and it should compile!
Alternatively, you could purge the old versions and manually install the latest with dpkg...
There may be easier ways to get the latest versions of those packages, but this worked for me. The point is you need those files provided in the cmake folder which older versions don't supply.
I want to put this here in case anyone else is having trouble compiling this on Ubuntu.
It seems the libsdl2=image-dev and libsdl2-mixer-dev packages don't come with the necessary cmake files in the older versions of Ubuntu.
The version supplied with 22.04 does not include the cmake folder: https://packages.ubuntu.com/jammy/libsdl2-image-dev
My Solution
Download the latest version of sdl2-image and sdl2-mixer: https://packages.ubuntu.com/noble/libsdl2-image-dev https://packages.ubuntu.com/noble/libsdl2-mixer-dev
Extract the files from the deb package (ex: dpkg -x file.deb new-folder)
Copy the SDL2-Image or SDL2-Mixer folder (located in the cmake folder of the extracted deb) to /usr/lib/architecture**/cmake folder on your PC.
Note that my architecture folder is x86_64-linux-gnu, yours may differ.
Alternatively, you could purge the old versions and manually install the latest with dpkg...
There may be easier ways to get the latest versions of those packages, but this worked for me. The point is you need those files provided in the cmake folder which older versions don't supply.
Credit to this post that pointed in the right direction: https://stackoverflow.com/questions/52813560/i-have-libsdl2-image-dev-installed-via-apt-get-but-cmake-cannot-find-it