I did both: nlDelete is again in longrat.h.
General routines (which do not know/do not need to know
the internal representation of the longrat numbers)
should use n_Delete(&p,currRing->cf) instead of nlDelete(&p):
is is more general and applies to all coeffient fields.
Specific routines can continue to use nlDelete(&p) because it is
slightly faster: it saves one indirection
(n_Delete(&p,c) is c->cfDelete(&p, c) where c->cfDelete is a pointer
pointing to the current delete routine, here: nlDelete)