[gcc r12-4265] libstdc++: Enable type traits for wchar_t unconditionally [PR98725]

[Jonathan Wakely <redi@gcc.gnu.org>]

https://gcc.gnu.org/g:4bdb9d618d30fc33d7eaab374baf377fa4e9d955

commit r12-4265-g4bdb9d618d30fc33d7eaab374baf377fa4e9d955
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Fri Oct 8 14:52:07 2021 +0100

    libstdc++: Enable type traits for wchar_t unconditionally [PR98725]
    
    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.

Diff:
---
 libstdc++-v3/include/c_global/cstddef | 2 --
 libstdc++-v3/include/std/type_traits  | 8 +-------
 libstdc++-v3/include/tr1/type_traits  | 2 --
 3 files changed, 1 insertion(+), 11 deletions(-)

diff --git a/libstdc++-v3/include/c_global/cstddef b/libstdc++-v3/include/c_global/cstddef
index 13ef7f03c12..a96319e31ef 100644
--- a/libstdc++-v3/include/c_global/cstddef
+++ b/libstdc++-v3/include/c_global/cstddef
@@ -73,9 +73,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   template<> struct __byte_operand<char> { using __type = byte; };
   template<> struct __byte_operand<signed char> { using __type = byte; };
   template<> struct __byte_operand<unsigned char> { using __type = byte; };
-#ifdef _GLIBCXX_USE_WCHAR_T
   template<> struct __byte_operand<wchar_t> { using __type = byte; };
-#endif
 #ifdef _GLIBCXX_USE_CHAR8_T
   template<> struct __byte_operand<char8_t> { using __type = byte; };
 #endif
diff --git a/libstdc++-v3/include/std/type_traits b/libstdc++-v3/include/std/type_traits
index 35ff5806c5d..d3693b1069e 100644
--- a/libstdc++-v3/include/std/type_traits
+++ b/libstdc++-v3/include/std/type_traits
@@ -309,12 +309,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
   // We want is_integral<wchar_t> to be true (and make_signed/unsigned to work)
   // even when libc doesn't provide working <wchar.h> and related functions,
-  // so check __WCHAR_TYPE__ instead of _GLIBCXX_USE_WCHAR_T.
-#ifdef __WCHAR_TYPE__
+  // so don't check _GLIBCXX_USE_WCHAR_T here.
   template<>
     struct __is_integral_helper<wchar_t>
     : public true_type { };
-#endif
 
 #ifdef _GLIBCXX_USE_CHAR8_T
   template<>
@@ -1828,14 +1826,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   // neither signed integer types nor unsigned integer types, so must be
   // transformed to the unsigned integer type with the smallest rank.
   // Use the partial specialization for enumeration types to do that.
-#ifdef __WCHAR_TYPE__
   template<>
     struct __make_unsigned<wchar_t>
     {
       using __type
 	= typename __make_unsigned_selector<wchar_t, false, true>::__type;
     };
-#endif
 
 #ifdef _GLIBCXX_USE_CHAR8_T
   template<>
@@ -1960,14 +1956,12 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   // signed integer types nor unsigned integer types, so must be
   // transformed to the signed integer type with the smallest rank.
   // Use the partial specialization for enumeration types to do that.
-#if defined(__WCHAR_TYPE__)
   template<>
     struct __make_signed<wchar_t>
     {
       using __type
 	= typename __make_signed_selector<wchar_t, false, true>::__type;
     };
-#endif
 
 #if defined(_GLIBCXX_USE_CHAR8_T)
   template<>
diff --git a/libstdc++-v3/include/tr1/type_traits b/libstdc++-v3/include/tr1/type_traits
index e62369c9f4c..16d7e338bfe 100644
--- a/libstdc++-v3/include/tr1/type_traits
+++ b/libstdc++-v3/include/tr1/type_traits
@@ -109,9 +109,7 @@ namespace tr1
   _DEFINE_SPEC(0, __is_integral_helper, char, true)
   _DEFINE_SPEC(0, __is_integral_helper, signed char, true)
   _DEFINE_SPEC(0, __is_integral_helper, unsigned char, true)
-#ifdef _GLIBCXX_USE_WCHAR_T
   _DEFINE_SPEC(0, __is_integral_helper, wchar_t, true)
-#endif
   _DEFINE_SPEC(0, __is_integral_helper, short, true)
   _DEFINE_SPEC(0, __is_integral_helper, unsigned short, true)
   _DEFINE_SPEC(0, __is_integral_helper, int, true)