after a few troubled days and with some help from alpine9000 I managed to compile and produce a valid adf file out of the sources, I followed the instructions but it was not so easy, I stumbled upon some code errors caused by updated libraries, files not longer available and more but at the end I succeeded.
To prevent losing the compile environment and to port it to other machine I decided to write a Docker image, so, if you have Docker installed on your system and you want to compile this game it's very easy and can me done with 2 instructions
1. git clone
https://github.com/alpine9000/climbyskies.git
2. docker run --rm -it -v #CLONEDGAMEDIR#:/project/repos/climbyskies ozzyboshi/climbyskies
The image is quite big (about 3 gigs) because of bebbo's gcc compiler that is mandatory to compile.
You will probably encounter a compilation error saying that the P61 files are missing, you can use your own music files to build this project or ask help from alpine9000 directly.
Don't look for them inside the alpine9000's github repository, he won't publish it due to copyright issues.