This is a GPL branch of Xdelta was maintained through version 3.1.0 (branch master).
The executables can be downloaded from the Release Page.
To build the tools for linux you can use Docker with the ubuntu and i386/ubuntu images.
Additionally if you want to use the build-all.py script you need Python 3.8.3.
Then you simply need to run the build-all.py script and the zip file with the executable will be in the build folder.