[libc] Add "struct tm" declaration to <wchar.h>

[vonosmas]

<wchar.h> should at least include the forward declaration of struct tm,
since it's needed for the wcsftime declaration (also, see https://man7.org/linux/man-pages/man0/wchar.h.0p.html).

Even though we don't yet have wcsftime, some downstream users (notably - libcxx) expects to see struct tm
declaration there, to re-declare it under std namespace:

llvm-project/libcxx/include/cwchar

Line 135 in c46bfed

using ::tm _LIBCPP_USING_IF_EXISTS;

So, add this type declaration to llvm-libc version of wchar.h now.

[llvmbot]

@llvm/pr-subscribers-libc

Author: Alexey Samsonov (vonosmas)

Changes

<wchar.h> should at least include the forward declaration of struct tm,
since it's needed for the wcsftime declaration (also, see https://man7.org/linux/man-pages/man0/wchar.h.0p.html).

Even though we don't yet have wcsftime, some downstream users (notably - libcxx) expects to see struct tm
declaration there, to re-declare it under std namespace:

llvm-project/libcxx/include/cwchar

Line 135 in c46bfed

using ::tm _LIBCPP_USING_IF_EXISTS;

So, add this type declaration to llvm-libc version of wchar.h now.

---

Full diff: https://github.com/llvm/llvm-project/pull/165795.diff

1 Files Affected:

• (modified) libc/include/wchar.yaml (+1)

diff --git a/libc/include/wchar.yaml b/libc/include/wchar.yaml
index c8b9e21b56b28..77af0fd4219e7 100644
--- a/libc/include/wchar.yaml
+++ b/libc/include/wchar.yaml
@@ -6,6 +6,7 @@ macros:
 types:
   - type_name: FILE
   - type_name: size_t
+  - type_name: struct_tm
   - type_name: wint_t
   - type_name: wchar_t
   - type_name: mbstate_t