#define remove_constraint(sys,cnst) do {xbt_swag_remove(cnst,&(sys->constraint_set));\
xbt_swag_remove(cnst,&(sys->saturated_constraint_set));} while(0)
#define make_constraint_active(sys,cnst) xbt_swag_insert(cnst,&(sys->active_constraint_set))
#define remove_constraint(sys,cnst) do {xbt_swag_remove(cnst,&(sys->constraint_set));\
xbt_swag_remove(cnst,&(sys->saturated_constraint_set));} while(0)
#define make_constraint_active(sys,cnst) xbt_swag_insert(cnst,&(sys->active_constraint_set))