Use functor/3 instead of =../2 plus arg/3

[pmoura]

Instead of:

DALI/src/examine_past_constraints.pl

Line 25 in eb30e1d

discriminate_dec_terms1(X):-X=..L,arg(1,L,Lc),

simply write:

discriminate_dec_terms1(X) :- functor(X, Lc, _),