Like BSLALG_DECLARE_NESTED_TRAITS, but for four traits.
BSLALG_DECLARE_NESTED_TRAITS
Declared in <bslalg_typetraits.h>
<bslalg_typetraits.h>
#define BSLALG_DECLARE_NESTED_TRAITS4(T, TRAIT1, TRAIT2, TRAIT3, TRAIT4)