None of these traits depend on libc support for wchar_t, so they should
be defined unconditionally. The wchar_t type is always defined in C++.
libstdc++-v3/ChangeLog:
PR libstdc++/98725
* include/c_global/cstddef [!_GLIBCXX_USE_WCHAR_T]
(__byte_operand<wchar_t>): Define specialization.
* include/std/type_traits (__make_signed<wchar_t>)
(__make_unsigned<wchar_t>): Remove redundant check for
__WCHAR_TYPE__ being defined.
* include/tr1/type_traits [!_GLIBCXX_USE_WCHAR_T]
(__is_integral_helper<wchar_t>): Likewise.
4bdb9d618d