Dear amadio,
Sorry for getting back to this only now, haven’t had time earlier unfortunately.
With your latest suggestion it worked, though I had to execute the first command (cmake . -Dxml=ON) in a separate directory as cmake did not want to spoil the source folder with the build.
So for reference and in case somebody else has similar issues, I did:
mkdir rootbuild
cd rootbuild
cmake ../root-6.12.06/ -Dxml=ON
cmake --build . --target XMLParser
cmake --build .
Thanks so much!
Cheers,
heico