Same as the two-argument operator== for mixed bsl/std strings.
Declared in <bslstl_string.h>
template<
class CHAR_TYPE,
class CHAR_TRAITS,
class ALLOC1,
class ALLOC2>
bool
operator==(
bsl::basic_string<CHAR_TYPE, CHAR_TRAITS, ALLOC1> const& lhs,
std::basic_string<CHAR_TYPE, CHAR_TRAITS, ALLOC2> const& rhs) noexcept;