delete a logical connector
int dellocon(ptfig, name)
Pointer to the figure in which the connector should be deleted
Name of the connector to be deleted.
dellocon deletes the connector called name in the figure
pointed to by ptfig. The list consistency is maintained, and the space
dellocon returns 1 if the connector has been deleted, 0
if no such connector exists in the list.
char *was_existing(p, s)
return dellocon(p, s) ? "you just killed it!
: "wasn't here anyway;