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