I can compile SeBa with gcc 11.4.0, but with 13.3.0 I get a whole bunch of errors of various kinds. Explicitly setting a lower C++ version only helps partially (see also amusecode/amuse#1159).
It looks like there's a lot of old Starlab code here that was written long before C++ got standardised, and that's definitely getting long in the tooth.
I'm going to have a look at this, because I'd like this to work in AMUSE.