[libcxx] [test] Portability fix: add missing header for std::max_align_t.

[amakc11]

Summary

Some tests use type std::max_align_t, but don't include <cstddef> header directly. As a result, these tests won't compile against some conformant libraries.

[ldionne]

Thanks! Do you have many other patches like this one? If so, could you consider lumping them together so I don't have to commit many of them?

[amakc11]

Look also at this revision.

[ldionne]

Committed as r347232. Thanks.

test/std/containers/sequences/array/array.data/data.pass.cpp

 //===----------------------------------------------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is dual licensed under the MIT and the University of Illinois Open
 // Source Licenses. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
 // <array>
 
 // T *data();
 
 #include <array>
 #include <cassert>
+#include <cstddef>       // for std::max_align_t
+
 #include "test_macros.h"
 
 // std::array is explicitly allowed to be initialized with A a = { init-list };.
 // Disable the missing braces warning for this reason.
 #include "disable_missing_braces_warning.h"
 
 struct NoDefault {
   NoDefault(int) {}

test/std/containers/sequences/array/array.data/data_const.pass.cpp

 //===----------------------------------------------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is dual licensed under the MIT and the University of Illinois Open
 // Source Licenses. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
 // <array>
 
 // const T* data() const;
 
 #include <array>
 #include <cassert>
+#include <cstddef>       // for std::max_align_t
 
 #include "test_macros.h"
 
 // std::array is explicitly allowed to be initialized with A a = { init-list };.
 // Disable the missing braces warning for this reason.
 #include "disable_missing_braces_warning.h"
 
 struct NoDefault {

test/std/utilities/memory/default.allocator/allocator.members/allocate.pass.cpp

 //===----------------------------------------------------------------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is dual licensed under the MIT and the University of Illinois Open
 // Source Licenses. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 
 // <memory>
 
 // allocator:
 // pointer allocate(size_type n, allocator<void>::const_pointer hint=0);
 
 #include <memory>
 #include <cassert>
+#include <cstddef>       // for std::max_align_t
 #include <iostream>
 
 #include "test_macros.h"
 #include "count_new.hpp"
 
 
 #ifdef TEST_HAS_NO_ALIGNED_ALLOCATION
 static const bool UsingAlignedNew = false;