+ * Revision 1.5 2000/10/08 12:02:41 mdw
+ * Use Euclid's algorithm rather than the binary one.
+ *
+ * Revision 1.4 2000/06/17 11:34:46 mdw
+ * More hacking for the signs of the outputs.
+ *
+ * Revision 1.3 1999/12/10 23:18:39 mdw
+ * Change interface for suggested destinations.
+ *
+ * Revision 1.2 1999/11/22 20:49:56 mdw
+ * Fix bug which failed to favour `x' when `y' wasn't wanted and the two
+ * arguments needed swapping.
+ *