-  xref_meta(+Head, -Called) is semidet[private]
 
-  xref_meta_src(+Head, -Called, +Src) is semidet[private]
 - True when Called is a list of terms called from Head. Each
element in Called can be of the form Term+Int, which means that
Term must be extended with Int additional arguments. The variant
xref_meta/3 first queries the local context.
- deprecated
 - - New code should use xref_meta/3.
 
- To be done
 - - Split predifined in several categories. E.g., the ISO
predicates cannot be redefined.
 - - Rely on the meta_predicate property for many predicates.