pub unsafe extern "C" fn gtk_constraint_new(
    target: *mut GtkConstraintTarget,
    target_attribute: GtkConstraintAttribute,
    relation: GtkConstraintRelation,
    source: *mut GtkConstraintTarget,
    source_attribute: GtkConstraintAttribute,
    multiplier: c_double,
    constant: c_double,
    strength: c_int
) -> *mut GtkConstraint