Create ecp_group_copy() and use it

library/ecp.c

@@ -181,6 +181,14 @@ cleanup:
     return( ret );
 }
 
+/*
+ * Copy the contents of a group object
+ */
+int ecp_group_copy( ecp_group *dst, const ecp_group *src )
+{
+    return ecp_use_known_dp( dst, src->id );
+}
+
 /*
  * Import a non-zero point from ASCII strings
  */