P1006R1 constexpr For pointer_traits<T*>::pointer_to() (#397)

Co-authored-by: Billy O'Neal <billy.oneal@gmail.com>

stl/inc/xutility

@@ -118,7 +118,7 @@ struct pointer_traits<_Ty*> {
 
     using _Reftype = conditional_t<is_void_v<_Ty>, char, _Ty>&;
 
-    _NODISCARD static pointer pointer_to(_Reftype _Val) noexcept {
+    _NODISCARD static _CONSTEXPR20 pointer pointer_to(_Reftype _Val) noexcept {
         return _STD addressof(_Val);
     }
 };

stl/inc/yvals_core.h

@@ -159,6 +159,7 @@
 // P0898R3 Standard Library Concepts
 // P0919R3 Heterogeneous Lookup For Unordered Containers
 // P0966R1 string::reserve() Should Not Shrink
+// P1006R1 constexpr For pointer_traits<T*>::pointer_to()
 // P1209R0 erase_if(), erase()
 // P1227R2 Signed std::ssize(), Unsigned span::size()
 //     (partially implemented)
@@ -997,6 +998,7 @@
 #endif // _HAS_STD_BOOLEAN
 #endif // defined(__cpp_concepts) && __cpp_concepts > 201507L
 
+#define __cpp_lib_constexpr_memory         201811L
 #define __cpp_lib_endian                   201907L
 #define __cpp_lib_erase_if                 201811L
 #define __cpp_lib_generic_unordered_lookup 201811L

tests/libcxx/skipped_tests.txt

@@ -554,9 +554,6 @@ language.support\support.limits\support.limits.general\functional.version.pass.c
 language.support\support.limits\support.limits.general\iterator.version.pass.cpp
 language.support\support.limits\support.limits.general\memory.version.pass.cpp
 
-# C++20 P1006R1 "constexpr For pointer_traits<T*>::pointer_to()"
-utilities\memory\pointer.traits\pointer_to.pass.cpp
-
 # C++20 P1023R0 "constexpr For std::array Comparisons"
 containers\sequences\array\compare.pass.cpp