The ADF* wrappers are not compiled with the library, however, the C ADF_* APIs are. The Fortran code is still available, but not compiled.
Enable the code and the tests in the examples/fortran/ dir.
According to CGNS documentation (https://cgns.github.io/CGNS_docs_current/adf/index.html):
Note: As of CGNS Version 3.1, the ADF core routines have been superseded by the CGIO interface routines, and any new development should use those instead.