[gcc r15-1553] libstdc++: Remove std::__is_pointer and std::__is_scalar [PR115497]

[Jonathan Wakely]

https://gcc.gnu.org/g:52a82359073653e312aaa5703f7e0ce339588961

commit r15-1553-g52a82359073653e312aaa5703f7e0ce339588961
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Wed Jun 19 17:26:37 2024 +0100

    libstdc++: Remove std::__is_pointer and std::__is_scalar [PR115497]
    
    This removes the std::__is_pointer and std::__is_scalar traits, as they
    conflicts with a Clang built-in.
    
    Although Clang has a hack to make the class templates work despite using
    reserved names, removing these class templates will allow that hack to
    be dropped at some future date.
    
    libstdc++-v3/ChangeLog:
    
            PR libstdc++/115497
            * include/bits/cpp_type_traits.h (__is_pointer, __is_scalar):
            Remove.
            (__is_arithmetic): Do not use __is_pointer in the primary
            template. Add partial specialization for pointers.

Diff:
---
 libstdc++-v3/include/bits/cpp_type_traits.h | 33 -----------------------------
 1 file changed, 33 deletions(-)

diff --git a/libstdc++-v3/include/bits/cpp_type_traits.h b/libstdc++-v3/include/bits/cpp_type_traits.h
index 4d83b9472e6..abe0c7603e3 100644
--- a/libstdc++-v3/include/bits/cpp_type_traits.h
+++ b/libstdc++-v3/include/bits/cpp_type_traits.h
@@ -343,31 +343,6 @@ __INT_N(__GLIBCXX_TYPE_INT_N_3)
     };
 #endif
 
-  //
-  // Pointer types
-  //
-#if _GLIBCXX_USE_BUILTIN_TRAIT(__is_pointer)
-  template<typename _Tp, bool _IsPtr = __is_pointer(_Tp)>
-    struct __is_pointer : __truth_type<_IsPtr>
-    {
-      enum { __value = _IsPtr };
-    };
-#else
-  template<typename _Tp>
-    struct __is_pointer
-    {
-      enum { __value = 0 };
-      typedef __false_type __type;
-    };
-
-  template<typename _Tp>
-    struct __is_pointer<_Tp*>
-    {
-      enum { __value = 1 };
-      typedef __true_type __type;
-    };
-#endif
-
   //
   // An arithmetic type is an integer type or a floating point type
   //
@@ -376,14 +351,6 @@ __INT_N(__GLIBCXX_TYPE_INT_N_3)
     : public __traitor<__is_integer<_Tp>, __is_floating<_Tp> >
     { };
 
-  //
-  // A scalar type is an arithmetic type or a pointer type
-  // 
-  template<typename _Tp>
-    struct __is_scalar
-    : public __traitor<__is_arithmetic<_Tp>, __is_pointer<_Tp> >
-    { };
-
   //
   // For use in std::copy and std::find overloads for streambuf iterators.
   //