freetree
extern void freetree(struct trenod *);
freetree(whptr(t)->whtre);
freetree(whptr(t)->dotre);
freetree(ifptr(t)->iftre);
freetree(ifptr(t)->thtre);
freetree(ifptr(t)->eltre);
freetree(regp->regcom);
freetree((struct trenod *)(n->namenv));
freetree(f->fndval);
freetree(forkptr(t)->forktre);
freetree(parptr(t)->partre);
freetree(lstptr(t)->lstlef);
freetree(lstptr(t)->lstrit);
freetree(f->fortre);
freetree((struct trenod *)f);