delete a physical reference
int delphref(ptfig, ptref)
Pointer to the figure in which the reference should be deleted
Pointer to the reference to be deleted.
delphref delete the reference pointed to by ptref in the figure
pointed to by ptfig.
The list consistency is maintainded, and the space freed.
delphref returns 1 if the reference has been deleted, 0
if no such reference exists in the list.
char *was_existing(ptfig, ptref)
/* if only one exists, it's this one */
return delphref(ptfig, ptref) ? "you just killed it!"
: "wasn't here anyway";