[libc++] Avoid including libc++ private header in std/ test

[ldionne]

Fixes #79783

[llvmbot]

@llvm/pr-subscribers-libcxx

Author: Louis Dionne (ldionne)

Changes

Fixes #79783

---

Full diff: https://github.com/llvm/llvm-project/pull/79856.diff

1 Files Affected:

• (modified) libcxx/test/std/containers/sequences/array/size_and_alignment.compile.pass.cpp (+4-1)

diff --git a/libcxx/test/std/containers/sequences/array/size_and_alignment.compile.pass.cpp b/libcxx/test/std/containers/sequences/array/size_and_alignment.compile.pass.cpp
index b7fb40c988678ae..209e24964807d91 100644
--- a/libcxx/test/std/containers/sequences/array/size_and_alignment.compile.pass.cpp
+++ b/libcxx/test/std/containers/sequences/array/size_and_alignment.compile.pass.cpp
@@ -22,7 +22,10 @@
 #include <array>
 #include <cstddef>
 #include <type_traits>
-#include <__type_traits/datasizeof.h>
+
+#ifdef _LIBCPP_VERSION
+#  include <__type_traits/datasizeof.h>
+#endif
 
 #include "test_macros.h"