__has_unique_object_representations is supported by MSVC (NVIDIA#4494)

Author: fbusato

libcudacxx/include/cuda/std/__cccl/builtin.h

@@ -930,7 +930,7 @@
 #  define _CCCL_BUILTIN_HAS_TRIVIAL_DESTRUCTOR(...) __has_trivial_destructor(__VA_ARGS__)
 #endif // _CCCL_CHECK_BUILTIN(has_trivial_destructor) && gcc >= 4.3
 
-#if _CCCL_CHECK_BUILTIN(has_unique_object_representations) || _CCCL_COMPILER(GCC, >=, 7)
+#if _CCCL_CHECK_BUILTIN(has_unique_object_representations) || _CCCL_COMPILER(GCC, >=, 7) || _CCCL_COMPILER(MSVC)
 #  define _CCCL_BUILTIN_HAS_UNIQUE_OBJECT_REPRESENTATIONS(...) __has_unique_object_representations(__VA_ARGS__)
 #endif // _CCCL_CHECK_BUILTIN(has_unique_object_representations) && gcc >= 7.0