[llvm-branch-commits] [libcxx] release/19.x: [libcxx] don't `#include <cwchar>` if wide chars aren't enabled (#99911) (PR #106788)

[via llvm-branch-commits]

https://github.com/llvmbot created https://github.com/llvm/llvm-project/pull/106788

Backport ec56790c3b27df4fa1513594ca9a74fd8ad5bf7f

Requested by: @ldionne

>From 914676e671ecff9bab6dfb65af7eadc87efe6542 Mon Sep 17 00:00:00 2001
From: Ties Stuij <ties.stuij at arm.com>
Date: Tue, 23 Jul 2024 14:09:34 +0100
Subject: [PATCH] [libcxx] don't `#include <cwchar>` if wide chars aren't
 enabled (#99911)

Pull request #96032 unconditionall adds the `cwchar` include in the
`format` umbrella header. However support for wchar_t can be disabled in
the build system (LIBCXX_ENABLE_WIDE_CHARACTERS).

This patch guards against inclusion of `cwchar` in `format` by checking
the `_LIBCPP_HAS_NO_WIDE_CHARACTERS` define.

For clarity I've also merged the include header section that `cwchar`
was in with the one above as they were both guarded by the same `#if`
logic.

(cherry picked from commit ec56790c3b27df4fa1513594ca9a74fd8ad5bf7f)
---
 libcxx/include/format | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/libcxx/include/format b/libcxx/include/format
index c3f2b45f0f7305..a88b3ef8528e2d 100644
--- a/libcxx/include/format
+++ b/libcxx/include/format
@@ -237,21 +237,21 @@ namespace std {
 #  include <cstdint>
 #  include <cstdlib>
 #  include <cstring>
-#  include <cwchar>
 #  include <initializer_list>
 #  include <limits>
+#  include <locale>
 #  include <new>
 #  include <optional>
+#  include <queue>
+#  include <stack>
 #  include <stdexcept>
 #  include <string>
 #  include <string_view>
 #  include <tuple>
-#endif
 
-#if !defined(_LIBCPP_REMOVE_TRANSITIVE_INCLUDES) && _LIBCPP_STD_VER <= 20
-#  include <locale>
-#  include <queue>
-#  include <stack>
+#  if !defined(_LIBCPP_HAS_NO_WIDE_CHARACTERS)
+#    include <cwchar>
+#  endif
 #endif
 
 #endif // _LIBCPP_FORMAT