prolog_clause:unify

unify_term(+T1, +T2): Unify the two terms, where T2 is created by writing the term and reading it back in, but be aware that rounding problems may cause floating point numbers not to unify. Also, if the initial term has a string object, it is written as "..." and read as a code-list. We compensate for that.
NOTE: Called directly from library(trace/clause) for the GUI tracer.